Some suggestions for the Duel server #4 and the Bookable server #3
#4
sv_alltalk 1 (allowing red and blue to communicate with eachother via ingame voice)
When it's not so much of a shit fight, remove the ability to play the following classes...
Sniper, Spy, Engineer
#3
mp_teams_unbalance_limit 0 (no restriction on what team you can join ie. everyone just joins red)
mp_autoteambalance 0 (there will be no teambalance in effect if the teams are unbalanced in anyway)