For me, I'm still considering private proxies - I think i might give them a try, but public are working out fine right now, I seem to have some decent ones that stay alive well and quite fast - just look here on BHW or google to find them, then test them - I use online proxy checkers as the SB checker never works well for me.
To be safe when I started with SB, I'd read that over-posting can damage main sites, So I created some sacrificial test sites, just to learn how it works etc
I grabbed a 000webhost freebie account and free co.cc domain and experimented on that to start - it indexed really fast (hours) and gained PR0 quickly (2 days at most) - I used a blend of manual higher DF PR comment posting and SB NF/DF blasting - all that was totally without niche focus and no keywords in the comment posting, just url. (basic site, mostly hand-coded php, about 6 pages + xml sitemap [submitted to Google])
I'm playing with another variant now - same again, using another 000webhost account and co.cc domain, but keyword in domain, some general non-keyword, url only mixed NF/DF SB blasts and some NF/DF SB blasts with keywords in the comments - same results, indexed within hours, PR0 within 2days - all going well too. (WP site, xml sitemaps, Google analyticator, cbnet ping optimiser, all-in-one seo - about 4 posts, freebie basic theme)
Both sites have Google Analytics (from the start) on but no adsense.
I've not touched them for almost a week, then will do a bit more work on them, I'm just waiting to see if I have a dance with bigG or get sandboxed.
I'm going to work on promoting deeper links next week to see how they go.
both of these will be satellite sites, that will point to main site(s)
In respect to SB - it's a great tool and can be used in many other ways than just posting, but do spend time on making the comments - make them always read well, as many as possible and as many spin variants as possible, it's worth it and leaves less footprints - same with email addresses, make loads and tweak often (you can get online address generators)
I also now have a list of foreign wp urls and translated comments...
Before SB, I either outsourced some linking or did it manually (time consuming).
I still outsource profile linking - i then ping these myself, then generate and push out RSS feeds of them.
hope that gives an insight to my approach.
(not saying I'm right or even a good example!)
Si