I would run a couple of tanks on the ground first. I use 15% fuel as well. Ive run several props on my 70, right now i have one flight on a 12x8 mas, so far i like it. Ive also used a 12x7 apc which was great too , and an 11x10 for speed. I think he 10x5 3 blade might be small, but i could be wrong. I wouldnt run higher than 10k rpm on a 4 stroke