Re: cruze control???
I use a bicycle lever type gear shift as a throttle. By adding a stop to the lever in an approiate place, the lever makes a fantastic thumb throttle. It naturally sits where my thumb lays on the bar.
On the 79cc bike the center screw is lighty tightened to retain the throttle position, the engine doesn't have enough power to restrain the bike (Vbrakes) even if I forgot to back off the throttle.
On the 212cc bike, the center screw is NOT locked.
Either bike's throttle is totally better than any motorcycle/ atv or electric throttle control that I have ever used.