12 x 4 should not be needed on that plane and that engine unless you are trying to hover with it. I'd go with an 11 x 5 or a 10 x 6, but you can really rev up a .46ax with a 10 x 6 if you insist on pushing that left stick all the way foward. I'll also second Minnflyer's suggestion to move the cg back a little. It will help the plane land slower and it will be more fun to fly as long as you don't go too far back on the cg.
