Looking for advice regarding the trim tab(s) for surfing with my 07' X2. I have a single center tab. Should this be up or down for surfing? Would it help to add separate P + S tabs on each side, as well? Otherwise, I seem to do well with factory ballasts, as well as a fat sac in back compartment on side of surfer. BTW, what does "KGB" ballast stand for? Thanks for any comments!