Rick, I agree with Bruce no way that handle gets that hot your idea to me is a great one. I have done three sets of wheels and inserts with paint and regular clear never had a problem. I used the high heat clear on the emblem no issues but that was metal. It was something to do with that plastic used on the end caps, handle and knobs at least that is my theory where the paint and the clear collided one or the other never really hardened. You avoided the paint it would be great if that solves the problem with the high heat clear over the dye.
You need to keep the thread updated when you get the grill in service if your using a cover taking that on and off you should see what kind of wear you get if any fairly quickly. I basically did not get 2 weeks out of it but that project was cursed from the start.
I can see it now people here pulling their turkey fryers out of the garage and using them for dye machines for their restores.