I bought a used 6 speed Regina extra freewheel and goes from 12-17T. The chain doesn't rub on the frame anymore, as it did with the 11T 7speed freewheel.
I upped the battery Amp to 65 and the Phase Amps to 140. Bike takes off smooth in my 2nd 57% speed now. 100% still cuts out if I hammer the throttle. Drilled a big hole into the controller case and added a fan. Still need to drill out two holes for fresh air to come in and add two fans. Waiting on some fan grills to come in.