For breakin I used an APC 14x10. Great vertical, pulls like a tractor, mph is down to the mid 105 range. My two cents is that the motor is turning in the mid 9,500 on the ground and as slick as this plane is I am sure it's unloading in the air quite a bit. I can't remember what the 14x11 turns on the ground. I bought a 13.5x12.5 to try. Haven't tried it though. One issue with these high pitched props is you don't get any dynamic braking with them. The plane on landing bleeds off speed very slowly.
