Only advice I will give is this:
Don't be a fuckin' Nazi with the moderation standards. I have quit visiting a Canadiens fan board permanently because they are constantly giving out warnings and bans on trivial issues. Some hot debate is good for a forum, not bad, and you will be getting plenty of that considering that tempers run hot when MMA fans talk about their favorite fighters. Allow plenty of leeway if you want people to stick around on your board...freedom of speech should prevail most of the time (personal attacks based on race/religion, threats of violence against, ect should be the only bannable offenses...not stupid things like 'fighter bashing' like they have on Sherdog).
Good luck with your project, and be sure to let me know when it's up and running...I'll definitely be a member there!