i wouldn't mix and match. i can't rememby why exactly but you would have to add an extra cap to get it right.
i would stick some 500's in there. i switched back and forth with my jagstang a few times, 250s then 500s then back, and then 500's again, i think when i sold it i had 250's in it again.
the single will essentially sound the same, but the roll off will be slightly different than a 250. and in reality, its worth getting both, and trying them out to see which you prefer. pots are cheap enough and soldering is easy enough that you can afford to switch back and forth to suit what your needs may be.
