1- If you want to get some authority to the web2.0 then you should have to post multiple articles on each web2.0. However you can get backlink by only posting 1 article.
2- You need to use private proxies to avoid accounts banning and to avoid footprints in big G.
3- To be honest if you want to get quality backlink then you should have to get hand written 400+ word article. However you can also scrape and mix articles and then can manually spin it using TBS.
4- There so many high pr web2.0 properties like tumblr, wordpress, bravenet, weebly etc
5- You can use all types of engines for t2 links because all links will give some amount of juice to these web2.0
6- You should focus on web2. 0 properties whose page rank greater than 3 because these links will have good authority and will have a good stick rate. To get the full quality and juicy links from web2. 0 then you should have to get the unique article with 1 link to your money site and one link to the authority site. You should have to maintain these web2. 0 by posting at least 1 unique or high quality spun article each week this will increase the authority of your site which link then pass handsome amount of link juice to your money site. While registrating on the web2.0 do not use your exact keyword (The keyword which are trying to rank) in the subdomain instead use some lsi keywords like if you want to rank a keyword "Car Cleaning Service" then use the automobileservices, truckmaintainance, buynewvehicles etc. This will not give any footprint to big G. Do not build all the web2.0 in single day try to drip feed these web2.0 and spread these on several days. After all try to boost these web2.0 with some tier 2 links.
Good luck for your business!
