[RyanN]

Just a personal preference here. 20AMPs

No science or anything behind my reasoning (well... actually there is, but I'm not going to get into the heat dissipation stuff...)

That little motor has to get rid of a lot of heat just at 20AMPs. At 30 or 40AMPs, I can see that motor going up in smoke in a hurry if something goes amiss. At 20AMPs, you at least have a few trips before it really starts damaging the motor.