Brake M/C rebuild...HELP!!!

This question, I think, is primarily for the twin owners. As I mentioned in another thread, my m/c is really gunked up and is going to need a rebuild. The problem is, what kind of rebuild kit do I need and where can I get it? Z1 has 2 rebuild kits, one is 1/2" the other is 3/8". My m/c has 1/2" stamped on the bottom which would indicate that the 1/2" kit should work, however my bike is not listed for use w/this kit. I talked to Jeff, at Z1, for quite awhile this morning and he seems to believe that my m/c piston is unique to my bike year (82) and model (750CSR) and the kit would not work w/my bike.(BTW Jeff is very nice and good doing business with.) Does anyone know if this kit will work w/my bike or if not, does anyone know where I can get a master cylinder rebuild kit that will work? Is it possible to clean up my piston and use the rubber seals and gaskets from the kit? Once again, any thoughts/suggestions are much appreciated.
Thanks again

(Addendum...my used parts guy thinks, if I bring the m/c and caliper to him, he can fix both , in less time than ordering parts. So, my problems may be moot, but I'd still like to hear any suggestions. I like to have multiple options, if possible. thanks)

I think I've got things handled. I took the brakes to Dean this afternoon, figuring I'd leave them there and pick them up when I pick up a little weld work, I asked him to do. He wasn't very busy and started looking at them while I was there. He had some stuff that he said was navel bilge cleaner. He started spraying the master cylinder and working the lever. I wasn't very hopeful that the seals were still good but he kept spraying and pumping. After awhile, he hooked up my caliper to the m/c, added some brake fluid and started pumping again. It wasn't long that he had the piston out of the caliper. By the time I left he had buffed the piston and cylinder and the whole thing was pretty much back in working order. The only thing that was left was finding a piston boot. Whatever this bilge cleaner was it seemed to do a great job and he said that it was something that he uses a lot around the shop and was the best thing he has ever found for cleaning up gunked parts. I'm still interested in the rebuild kits because I think I'm gonna do a real teardown/rebuild overwinter but it looks like I'm still gonna have it running real soon.