I wouldnt recomend the twist throttle especially if your wife is just learning to ride. Ive got one(Taking it off now) and its got me in troube several times. If your jumpin and land your wrist automatically drops down=WOT
If your climbing a steep hill, wheels come up and your hangin on its hard to back off the throttle. Everytime you pull the front brakes hard the motors gonna rev.
Everybody likes different setups but becuase of that 1 im buyin a new axle, hub, headlight, exhaust bolts and rewelding a +3 swinger that i just put on and it broke in half.
Just something to keep in mind, I wouldnt put put one on my wifes bike.
Good luck with everything else tho, Jeremy