I've got a Dimarzio SD100 waiting to go in my RG321. I'm going to go ahead and order an Air Norton to go in the bridge and just wanted to know what I should do about the pots. Whatever's in there now is what came stock. I don't know jack about this kind of stuff so tell me if I'm wrong, but, I was thinking 500k volume and tone?
500k pots are the norm for humbuckers with .047uF(microFarad) capacitors for the tone pots in most cases.

For single coils, use 250k pots with .022uF capacitors for the tone pots.