No so much the caliber as the action. 9mm is a disadvantage because it scores minor ONLY in Limited or L10, and since it is a single action model 226 it can not compete in production. Your best bet would be to either compete with what you have and buy 10 round mags for the .45 OR get a Production gun (XD, Glock, SIG 226, Berreta 92, ect) and shoot cheap 9mm's in production until you get the hang of it.
More guns is generally better right?