It pays to experiment with props, but I don't think a three blade is going to help you any. If you want more low speed performance I would try a 16 x 4. For more speed, I would try a 14 x 8. These gassers don't turn up the rpms like a glow engine, and therefore if you pitch them too low, the speed falls way off. But because of the torque they have, you can use a larger diameter which really helps with the thrust. Three blade props are generally less efficient than two blades. Hopefully you are using APC props, as they really seem to work better by quite a bit than the other brands. I think overall you would like the 14 x 8 unless you are really looking for 3D performance, in which case a 16 x 4 would be worth giving a whirl.

Thanks for the update and keep us posted,
AV8TOR