what's the purpose behind 301? Will you use it as a spam/sape buffer or just trying to leach out the existing link profile?
Please don't confuse SAPE with the 301. SAPE is a blog network. In both SAPE & spam, you build
backlinks to your site. 301 is totally different.
301's are used to tell search engines that a domain/url is moved to a new location and old location shouldn't be indexed or listed on SERPs anymore.
Let's say you've a domain called domain1.com with 1024 backlinks pointing to it from several high PR and authority pages/sites. With the help of backlinks, the domain is ranking high on Search Engine results. Since it has quite a few backlinks from authority sites and the domain is aged, it holds some good authority in the eyes of Google.
Now you 301 domain1.com to domain2.com but the domain2.com has zero backlinks. What'll happen now is almost all the authority that the domain1.com is holding on will be passed on to the domain2.com. The indexed pages for the domain1.com will be slowly removed from the SERPs and the domain2.com's pages will take over that place.
The domain1.com doesn't have to be relevant to the domain2.com in order to pass the domain's authority.
What happens now is when everytime search engine spiders crawl through the domain1.com's backlinks, it'll pass and push it's authority to the domain2.com while domain2.com will be drawing in all the authority to itself and growing enlarge in the google's eyes.
Now you build a bunch of high quality relevant backlinks via guest post or web 2.0's to domain2.com.
With all the authority it is holding already, and now with the help of all these relevant backlinks, it'll skyrocket on to the top of search results cos Google now sees domain2.com as both relevant and an authority site.