Depends on how you use the RB's. Ricky is the best out of the 4 you listed in almost every scheme. George is the best power back listed, and James is the best receiver. AP is just a bit of a step down from Ricky, but fairly similar. Since you have Spiller, I'd stay away from James. If you change HB's to gain a few coins, pick up a Deion and put Peterson as your SS. Peterson is probably the best corner to put back there due to his 89 tackle. If you like the 2 hb read option, oregon is the way to go. I know there is one formation in particular with them that with a package puts a HB as the only receiver on the left, and motions him into the backfield on most plays, something that would be nice with Spiller.