Just bought 7 domains to start a network

I've been wanting to set up a network for a little while now.. yesterday I finally pulled the trigger and spent about $250 and got seven domains (two PR2, three PR3, two PR4) that are relevant enough to my current clients. I'm planning to host these on my business's VPS, and I'll buy a dedicated IP for each domain. I've been reading good things about SickNetwork. Is this something you guys have played with? What're the other options if there's any decent ones? I plan on having around 25-50 domains after I set all this up and see some results.

What strategies do you use when linking to client/money sites? I've seen only sidebar links... contexual links in articles that are always on the front page.. footer links.. etc. How many links to a client site would be best? I don't mind limiting links on a domain to conserve authority. These things are gonna pay themselves off quickly. Also, how long should I wait after setting up the website + some content before linking my clients?

And lastly.. how limited am I to blasting these network sites with link building software? I'll be managing the network sites' posts myself, I'm just concerned about backlinks

Would love to hear some experienced opinions

How did you find the domains?

I'd just put them on random webhosts instead. If the IP's are not diverse enough, that might become a footprint.

Use different template/theme, make them legit, and repurpose content from Wayback Machine.