I would suggest several: 10 X 7, 10 X 8, 11 X 7, 11 X 8, maybe an 11 X 9, 12 X 6. If you are going to fly pattern with it, look for the prop that will give you a nice constant speed plus vertical, without being real zippy (too fast) in straight and level flight. I'm betting an 11 X 7 or a 12 X 6
Regards,
GPB