FWIW...it's really not as much of a hassle as you might fear. There are only two different thread pitches used, most are the "standard" pitch for their diameter and very few M10s. From memory, the K1-`79 folding bar clamp uses the coarser thread pitch and the hex nuts are an odd size. The M8 hub-to-wheel hex nuts have the typical thread pitch used with M8s but, the hex nut diameter is 14mm, instead of the normal 12mm. The kickstand pivot bolt nut is an odd size, too...but a standard thread. The seat hinge pivot bolt is a proprietary fastener but, the M6 hex nut is garden-variety 1.0 pitch. Lever pivot bolts are proprietary but, you could use bushings, or a little creative lathe work (depending on the specific bar/level combo) to adapt stainless.
You only have to deal with a few oddballs. The highly-visible fasteners...upper engine guard, plug guard, tank bracket, battery carrier, tail light bracket, seat hinge, seat latch, headlight, wheels...as well as most of the not-so-visible...fenders, footrest bar, speedo, are all garden-variety M6 & M8s.
Engine screws are all M6/1.0, except the semiauto clutch adjuster nut, which is the same as the wheel-to-hub nuts. No reason why you can't use an M8, 12mm, hex instead...it might look a little small but, once you're going to all allens who's gonna complain?:34: