Two years and counting on mine, and still have the powdercoat sticking perfectly. I often stuff my shoes into the wheels themselves to get high enough into the engine compartment, and even that does not scratch them. Pretty tough stuff. IMHO prep is everything, regardless of going powdercoat or rattle-can. Mine had absolutely 100% of the chrome removed. Scuffing may not do so well, as the chrome was bubbling-off of the Alu...galvanic-corrosion was the problem with mine. No such issues with paint!
Did you fully remove/grind through the chrome plating? I spoke to a sandblaster/powdercoater and he was saying just ruff up the chrome. From you original post it sounds like you ground all the way through?
Thanks,
I have been debating trading or selling my chrome domes but think I will just start grinding. I have them un-mounted and it's just a lot of chrome looking me in the face. I will probably prep just beyond the lip and not worry about what the tire covers and forget about the nooks and crannies of the back of the spokes