Vintage Dirt Bike Q & A

Just found out that the rim of my MR 250 has cracks and looking at some other old posts this seems common. This bike uses the same rim as the CR250m,m1 and m2 and some XL350. I don't race but was wondering what others do? I don't think the ebay option is good, what are the chances I could find a crack free rim when mine is broken with 1,500 miles on it? Should I look for nos one, or something like an excell one? Would using an aftermarket one on the rear and the original on the front look strange or do they look close enough? Any recommendations on a wheel builder? Thanks Gary