questions about neuter after-care

My bucks are getting neutered next month--two at a time, a week apart (I currently have four boys living in one huge Martin's cage). I'm neutering them because I'm having some aggression problems: Olie and Metro do *not* get along (actually, Olie is having probs with everyone; I'm sometimes tempted to separate him).

Would it be best if I separated the boys while they recover from their surgeries? Metro and Kono are going first; Calle and Olie a week later.

I also suspect it would probably be best if I used newspaper beneath paper towels or cloth towels while they recover--am I correct?

Are there any other concerns I should have? These are my first rats, so I'm about as newbie as you can get.

--Victor and the boys.