The sky is the limit, if you can use any cartridge besides a 6PPC.
How serious do you want to be?
Budget?
Does the rear bag you have, fit properly to all of your stocks?
If you are using a sporter forend of some kind, a forend 3" wide bag rider would help a lot.
I do not sell or have anything to do with these, but they are the best I have seen.
I like them enough to put their website on my price list, because a lot of people ask me about how to have more consistency off of their front rest and rear bag set-ups.
Precision Shooting Accessories
ljwprecision.com