DS design strategy

I was looking at the Dirtside design rules and my
"Slammer" tank.  The temptation, looking at the
tank, is to give it and MDC/4 for the big gun
and a RFAC/1 for the turret on top of the turret.

>From a game perspective does this make sense?	Since
you can only fire at one target with only one weapon
should I make that smaller weapon a APSW?  I guess
in Real Life(tm) that would be some type of APSW anyway.