The 821 on throttle is a good choice, it should hold up fine. For choke you can use any old servo, and in fact a well worn servo might be preferable.

The choke will snap into place at fully open or fully closed. If your servo just gets it pretty close that's really good enough, and less precision means the servo is less likely to be drawing current trying to stay in that exact position. A little bit of slop here is a good thing.

TF