The only difference is that I added two towers which are mostly underwater containing a generator each. The gens power entrance forcefields to the main base. Only one gen is repairable. I also added two turrets and waypointed the turret power. It plays fairly smooth as long as there is at least 8 players. It plays better when there is more. The object of the towers is to give the defense more then 8 seconds to setup their defenses. I call it the KamikazeSamurai defense system!

Thanks to Bytor for letting me resubmit with pictures.

Check out my original server-side map Ascension. It is an awesome siege map incorporating a skybase and grav-elevator.