I had a old space saver tire mounted on a correct rim a few months ago with the help of my friend Gary (moparman440) at his shop and it was not an easy job by any means!
I had painted the rim prior to taking it Gary's shop and there were a number of scratches in the paint after we were done. With all the wrestling around on the tire machine with at times, 3 guys fighting with it with tubs of lube and metal bars, I am surprised that tire didn't get ripped apart and the wheel itself get bent up in the process!
I had to do some touch up painting work after I got the assembly home, but it ended up looking great.
I don't see working with a powder coated wheel coming out well.
Thanks again Gary! And thanks Jules, after about an hour, we were about ready to give up trying to get the tire to seat, Gary did a search here, and after reading this thread, we wrestled with the tire a little more, tried inflating it completely which I had been afraid would permanently distort the tire, and doing that, we got it to seat!