If the 4" point is stainless, theres no worry about rusting there. I would paint the rest high temp black. The ones I have made I just used mild steel. I treat the hot dog end as if it were cast iron. Season it with some butter or cooking spray and then slow cook a couple hot dogs on it until they are black. Then spray it down good again with some spray butter or whatever and it should be good for a long while as long as it doesn't get wet. Now after that complicated explanation, here is a brief one. Treat it as cast iron. lol
So much to read, so little time.
If you consider yourself a master of something, does that mean you refuse to learn anymore about it ???