[rotorwrench]

The stretched spoke will tend to push the rim off straight so I see no other way to do it. A person can be surprised how much shrinking can be done without getting carried away with the quench. A compressed air nozzle will cool it from a dark cherry color without getting it wet. Heating it too much and quenching too fast would be more stressful for the steel.

The best solution is a new wheel but some wheels don't need much work and will be plenty strong for a light weight and slow model A.