Where can I hook up an electric choke?

I never said it couldn't, I said the pressure switch is a better idea. If you hook to ballast, it will have power anytime key is on running or not.

Not sure I agree as to "why." The switch just adds more complications, and anyone alert to their vehicle should not be leaving the key on in any case. It certainly is "another way" and there is certainly nothing wrong with that method.