Mike;
If you have access to electroless nickel plating, I'd recommend that for your parts. It will probably be limited to parts of a certain size due to the tank size of the plater. Electroless nickel is unique in that it can plate internal threads, blind holes, etc. I used it to plate the cylinder walls of a Corvair engine that I built. The plating hardness can get pretty high by heat treating. Pretty low friction coating, too.
Regards, Neil Tucson, AZ