I've built over 1000 pbns with a combined value of $150k-$200k from the domains alone.
I have helped dozens of clients achieve extraordinary levels of success and 100+ good success. (I'm not going to lie here and say I've helped every client get crazy results. This isn't possible, but I've helped a lot of clients get anything from small boosts to huge 10x+ increases in traffic)
I have direct experience helping clients make on-page changes and seeing both positive and negative impacts. Learning from both.
I have direct experience siloing existing sites for clients.
I have direct experience analysing client sites, recommending changes for positive growth and pointing out issues that are causing problems. In 70%+ of cases I have been able to help clients get a good result.
I have built and silo'd both my own affiliate sites, and client projects from scratch. I currently have a 100% success rate and my best affiliate sites have reached 5 figures per month.
Overall I have a broad range of SEO experience due to my exposure to a LOT of client sites, in a lot of niches. All sorts of sites.
All my knowledge comes from practical experience. I don't read about SEO. The occasional case study, but generally the SEO blogs are all full of overly complicated and conflicting advice. Hence I am not regurgitating information from other sources.
Exactly as outlined in my guide on the forum.
https://www.blackhatworld.com/seo/the-ultimate-guide-to-seo-siloing-dominate-google-in-2018.985967/
You need to silo an entire website. You can't pick and choose. I may be misunderstanding that part of your question. Ie, you can't just silo "some articles."
Here's the first re-usable question and answer, so just to further explain from above, I will re-word what you're asking here into a more re-usable question and answer.
Q1) Do I silo using pages or posts. What's the difference?
A1) Both. You need pages, post categories, posts and 2 plugins. Here's the procedure. (Note, there's several ways to silo, but this is an easy way to do it)
I'll use an example to make it more understandable. L1 = level 1 silo. L2 = level 2 silo. L3 = level 3 silo and C = Child post, ie, article. This is my standard terminology from now on.
L1 = animals
L2 = animals/dogs, animals/cats
L3 = animals/dogs/akita, animals/cats/siamese
a) Install this plugin https://en-gb.wordpress.org/plugins/permalinks-customizer/
b) Create the following post categories. animals, dogs, cats, akita & siamese. You can organize them with the correct parents, but this isn't needed. It makes it easier to view your silo structure in the category section so I do recommend this.
c) Create your first child for animals/cats/siamese. Normal wordpress post.
d) Select categories animals, cats & siamese. It is all 3.
e) Under 'document' on the right, you'll see the permalink section.
Ok, so now we've got animals/cats/siamese/article-name. These aren't categories. They do not exist just now. They're just a permalink structure. They have NOTHING to do with the post categories we created above. We will have a use for those later.
f) Create a PAGE 'animals'
g) Create a page 'cats', make its parent page 'animals'. (You do this on the right in the editor, "page attributes"->"parent page")
h) Create a page 'siamese', make its parent page 'cats'.
Now, these are your SILOs!
i) Create 75-200 words of text at the top of them. No more.
j) Install a plugin that lets you list all posts in post categories. I am not going to tell you the one I use, because I don't want a bunch of copy cat sites looking the same as mine
There's plenty. Find one.
k) On the animals page, list all posts in the animals category AND all L2/L3 silos, which each have a post category. Ie, animals, dogs, cats, akita, siamese. This would literally be EVERY SINGLE animal category, L2, L3, L4 etc.
l) At the bottom, under the posts, link to every silo under animals, in a tree structure. Format it any way you want. The key is to link from animals to dogs, cats, siamese, akita, everything, so juice is flowing down everywhere from the animals silo.
m) Do the same for dogs and cats, all the way down your silos. So dogs displays all posts in dogs, akita and any dog breed silo.
Remember, you could have a general animal article, just in the animal silo, a general dog article, just in animals/dogs, or then an akita specific article, in animals, dogs and akita. So an akita article will appear on the homepage, animals, dogs and akita. You do not want to try to rank your silos for too many keywords. That isn't the point. You are not trying to rank for "akita" or "dogs". Of course if you build up a beast of a site, you might very well hit page 1 for dogs with a silo structure. BUT, you know you're on the right track when you're page 6 or 7 for 'dogs' and page 4-5 for akita etc. Your silo title will be like "Animals", "Dog Guides, Breeds & Training". General, generic, broad. You'll rank on page 4+ for "dog guides", "dog breeds", "dog training", "dogs", "breeds of dog" and so on. The goal here is to build topical relevance for dog guides/breeds/training/info. The broad stuff, and pass that juice down to all your articles. You are grouping it all together so google sees your broad dog topic and your sub-topics and understands you have a lot of content about all these topics. You become an authority in animals, when you have 30 level 1 animal silos, each with another 30-40 level 2's, each with another 30-40 level 3's
You'll become an authority in akita, when you have 5, 10, 20 articles in there. The more the better. Unique and high quality though, not repetitive junk. Then when you become an authority in akita, rotweiller, german shepherd and 10 other breeds, you'll become an authority on the parent silo. You see how it works? So focus in on 1 low level silo at a time. Don't have 1 article per silo. Build them up in groups, focus on 5-10 dog breeds and the dog silo, then 5-10 cat breeds etc.
You don't create a silo with 3000 words of content. That's not a silo, it's a child page. Google will never see you as an expert in dogs, if you have 1 big generic dog article. It wants to see 100's of articles on a broad topic like dogs, covering every topic, breed, training, health etc Imagine from the example above you just have a 3000 word article on dogs. That's just going to rank for some longtails, and even worse, the silo page will compete with inner pages. It'll be a mess.
Don't over-think it. Link what's natural. If you need to link from cat to dog, do it. You'll more often than not link from dog breeds, to training, and other dog breeds and so on, but cats ARE related to dogs, and it is natural to link, so all you are doing is strengthening your topical authority and helping google understand how all your content connects together. With the above structure, you've got the core covered and google will understand all the topics you write about.
No, no, no

You don't rank silos for long tails. Don't try to rank 1 page for something another ranks for.
You don't want to rank silos. They are for passing link juice. If you eventually rank your broad keyword silos, then cool, but 80-95% of all traffic comes from longtails, and the best converting traffic comes from longtails. Ranking your silo in the top 100 for the broad terms is enough. That tells you google knows what your silo is. If you aren't ranking in the top 100 for your silo for any broads, then you've done something wrong. Note, SOME broad. You probably won't rank for 'dogs', but you should rank for 'dog information' or 'dog info' or something broad. Check ahrefs/semrush and this tells you how google sees your silo. If it doesn't rank at all, or it's ranking for longtails, then you have done something wrong.
It's a good question. I will make it a re-usable
Q2) Can I rank a silo'd site without backlinks, or with limited backlinks and if so, how much content do I need?
A2) Yes, no and probably.
Zero backlinks? Probably, yes. But for that I would estimate you need 1 million+ words of content on the site and 18 months to 2 years.
Minimum backlinks.. Perhaps a 2-5 guest posts and a couple of good pbns a month, around 300k words of content and 1 year.
And if you're backlinking more aggressively, 5-20 guest posts a month, and 5-10 pbns per month on an aged domain(I only use aged domains if I'm doing more aggressive backlinking, especially pbns. You don't want more than 10-15% of your links to be from pbns, ideally 5-10% max. It was different a couple of years ago, but things have changed in the pbn world in 2019.)
I don't do any sort of backlinking other than guest posts and pbns. I don't like niche edits. Had mixed results. web 2's, comments, forum posts, press releases and all that other stuff is just fluff. Even on a completely fresh domain I wouldn't bother. Some web 2's, sure, the rest, no need. Press releases if you're a real business. Just regular guest posts. Paid links. Contextual can be relevance or not relevant. Doesn't matter. An article about dogs on a tech site is relevant. Tech for dogs. A story about an engineer's dog. A robotic dog. For non-contextual, sidebar, footer, paid directories, any sort of list you want RELEVANT. Footer must be relevant. Get a footer from a tech site to your dog site and you're in trouble. pbns, starting with a couple in month 1, maybe 3-4 in month 2, 5-6 in month 3 then 5-10 per month. But I always start with relevant aged domains for money sites. Makes things easier. You've already got a ton of links, so you just start building plenty of guest posts/pbns and rank. So, finally, if you are backlinking like that, 3-6 months on an aged domain, 6-12 months on a fresh domain and about 100k words of content.
You don't want to rank silos, category pages, tag pages, archive pages or anything like that. Even your homepage you don't really want to rank. Just child pages for your longtails. That's where the money is. Siloing is BIG. You go big or go home. 100k words MINIMUM. Ideally 1 million words if you want to absolutely slaughter your competition, then stand on top of a mountain of corpses, laughing hysterically.

I'm not joking. Do my silo structure above with 1 million+ words and you will be utterly amazed at what you see on semrush for your site.