John,
Hope you have some positive response from across the pond for Challenger front steels.
I was very pleased with the replacement steel rims and spokes Detwiller's of Wisconsin did on my styled Red Challenger front wheels a few years back before it came from Dennis Brown, it was the only way I could see me getting the tractor on all steel. They look even better now with the skid rims fitted which Gwil made for them in North Wales.
Good luck,
Malcolm.