Just web2, always seems to do the trick, and most my sites stick a good couple of months and longer. They are all gambling related so pull in good money before they die. The way I see it, is there is no point hanging around making no money trying to play it safe, when you can make a splash page for 50p, beat it to death and it pulls in a couple of thousand a month.
Most of the time I blast them straight off, mostly with fiverr gigs or bst web2 gigs.
How many links are we talking here? 1,000 10,000 100,000 a day?
I have some sites that I "blast" and do the same thing to and then scrap after each update, but my definition of blast is probably a bit different. I use all types of links mixed in and a few hundred per day only. I automate web 2.0, wiki, article, documents, videos, blog posts, bookmarks, blog comments. I also keep sites that I "love" separately. The funny thing is, my toss away sites and my keepers use very similar backlink strategy, except the link velocity is completely different.
As for the OP, you want to build some authority to your tier 1 properties. There are a few ways to do this but there is a synergistic effect when you do all of them.
1) Add more unique posts to your tier 1 properties
2) Make sure not every post on your tier 1 points to your money site. Use some of them to point to authority sites in your niche as well as internally link individual posts within the same property together.
3) Add pictures and video to them to make them multimedia rich.
4) Backlink them like you would your money site, but use automated tools to accomplish it on scale.
5) Get your tier 2 backlinks indexed by "blasting" them. You won't even have to try and index your tier 1s, they should index by themselves in no time.
6) Optional: If your tier 1 content is actually really good, there are ways to internally funnel do-follow link juice from other bloggers using the same platform. (not all properties can do this)
After you've done this, you should at least be on page 1. From here, analyze the backlinks of all your competitors in top 5 and match all the high quality backlinks that they have. Good luck!