How many web 2.0 should I build for my new long run site?
well, it really depends on the keyword competition, website age and authority
make sure to buy/build quality ones over too many trash ones, especially for the 1st tier
How many articles do I post in each Web 2.0? And please suggest the best article spinner.
i would go for something about 1-30 articles, depends on the web 2.0 design and structure,
you have to them look as natural as possible and continue to post from time to time or update the content
Can I use a Web 2.0 tier or not? If I can use it, which Web 2.0 should I put in Tier 1? And which Web 2.0 should I put in Tier 2?
yes, you can use it for both 1st and 2nd tier,
use well-known web 2.0s for your 1st tier that won't get deleted in a couple of weeks (Wordpress.com, Weebly, Yola, Jimdo, etc...)
you can use all the others for the 2nd tier (automated)
What is the best way to index Web 2.0?
you can use social media shares, indexing services, blog comments...
Can I use GSA Blast or Automated Web 2.0?
yes, go for contextual ones that might get a good indexing rate
overall, you need to make a real looking website as much as possible for these web 2.0s,
this includes logos, favicons, meta titles and descriptions, about, TOS, contact pages, etc...
also, try to post a few articles to the web 2.0s before adding your link
if you put good investments in such web 2.0s, along with crowd, PBNs and guest posts it could be really beneficial