Q:

Is it good idea to redirect (301) domain+links without "Address Change" in Google Webmaster?

Lets say, I want to move most of my site content from example.com to a1.com, but also want to put i.e. 20 pages to a2.com.
Mainly I care about page-rank to be transited well.
what are best way to do that? Should I use Address Change tool in webmaster and  .htaccess 301 redirect everything to a1.com (except those 20 links- redirect them to a2.com)
?

A:

The change of address tool is meant to move the whole domain to a new domain or subdomain. First you need to setup the 301 redirects and then let Google know about the change of URL through this tool.
In your case, I'll not recommend using the change of address tool cause you can get Google Bot confused: you are changing to a new domain but at the same time you are redirecting some URLs to another domain.
Check Google official guide:

Don't chain site moves. If you submit a change of address to redirect traffic from site A to site B, you can't immediately submit another change of address from site B to site C.

I'll use 301 redirects and updated sitemaps for each new domain.

