[HotnCold]

On the shaft - Grind a flat spot - not too deep - just a flat spot with a dremel - and about half the total length of the exposed shaft should more than do. Dont know about the blue wire and such - dont have that controller - however you could solder them - if it drives backwards then reverse the two outside wires and resolder ( thats the way i do it on my controller anyway ). Keep your battery wires as short as possible - Thats all i can say about the length. A hotter soldering iron is best -
The only way i can describe the solder technique i used is is like this -take your two pointer fingers and put them together ( pointing towards each other) thats the way you want to solder the motor connections. Tin each of the wires on the motor and the speed controller - Hold the two wires together ( after putting shrink wrap on one wire ) and hit the tips with a nice hot iron - It should work perfectly.... Hope this helps ya..