You know, in retrospect...
If you're thinking of putting up a server, do what you feel is good. This approach has worked in the past.. asking opinions is great but if you're going to do that level of work, you should do what you enjoy to keep the frustration/tedium to a minimum.
If you're set on a 3 sided, maybe brainstorm ways to keep (like posted above) it from becoming a blowout if things swing heavy one way or another.. or another
Compensate for the playerbase.
Build it and we will come, that much I'm sure of.