Hey,
I can try to help..
I think it really depends on whether all your sites are hosted on the same IP. If they are all connected to each other and have the same IP then this looks like a
network. Google looks for patterns and may discount some of these links although I don't know whether you could get a penalty.
If the IPs are different and the sites are very relevant in content then you should definitely keep "do follow" links. Google will value these individual sites more because they will have quality and relevant links.
You may want to optimize your linking pattern as well to avoid closed loops. Bootycraze gave this example to avoid that a website links to itself:
WebSite 1 Links to 2 3 4 5
WebSite 2 Links to 3 4 5 6
WebSite 3 Links to 4 5 6 7
WebSite 4 Links to 5 6 7 8
WebSite 5 Links to 6 7 8 9
WebSite 6 Links to 7 8 9 10
WebSite 7 Links to 10 11 12 1
WebSite 8 Links to 2 3 4 5
WebSite 9 Links 3 4 5 6
WebSite 10 Links 4 5 6 7
WebSite 11 Links 5 6 7 8
WebSite 12 Links 6 7 8 9
To get links from different IPs I usually set up
blogs on free hosting plateforms, like Blogger or Wordpress. There are a ton of those, do a search for "free hosting
blog". I create some mini sites that are relevant to my main site and direct all their links to it. My main site has its own domain of course. Because all the mini sites' outgoing links are directed to my main site, they are powerful in the eyes of Google.
Alternatively, you could use seohosting.com which gives you one different C-block address per site. I am about to join them and could give you some feedback if you're interested.
Anyways, hope this helps a little bit,
-- Sebastien