30:1 on an astro 25? very fast that, 100:1 on standard 540 motor is about the same torque but a lot less cash. (without doing any maths on torque im making an educated guess).) i have some of these for sale if you think they might be suitable.

as to the spinner, listen carefully to geoff and john from scorpion, i am sure nobody in the uk knows more about these in this application, and problems that occur as a result. shame you gave up on the nitro engine though