Hi Ken,
Thanks for your interest in the 766. Currently the prototype has been flying with 139t main gear and a 12t pinion(11.58 ratio). With this ratio you'd be able to get a max head speed of 1950ish on 12s with a 450kV motor, or just over 2200 on 14s. As to your other question of pinions available, the 766 will use the same pinions that are already available, 12t - 15t. That will give you gear ratios ranging from 11.58 - 9.26. I hope this helps!
