I use a Mejzlik 28x10. That is the best prop for pattern due to the uplines. A 26x10 makes 3D a whole lot easier due to hovering at 1/3-1/2 throttle as apposed to 1/4 or less with the 28x10. (there just isn't a very concentrated flow of air going down the fuse with the 28x10 which makes the tail very slushy in 3D and if you give it a little hit with the throttle to bring the tail back under it you just climbed 15-30 ft.)

It doesn't mean you can't torque roll, it just means you have to stay on top of it better so that it doesn't fall off a bit b/c it isn't coming back even with 45 degrees of rudder. It will come back with elevator though.

Helps keep me flying the sequence instead of goofing off with the 3D the whole time. Uplines with the 26x10 are horrible. If you just want to buy 1 prop I would get a 28x10. You can break it in with that too if you want. Just be sure to tac it