That's good news about the cylinder bores and pistons. Do you stick to the recommended oil change interval, or change it more frequently?
Did you mention that you had bought a set of standard size Kawasaki rings? I think I read somewhere (maybe David Ewing mentioned it) that Kawasaki improved the durability of the rings at some point - maybe from A3 model onwards?
Have you given much thought to the primary & secondary chains? I recall Kawboy's explanation of how the valve timing and therefore compression can be affected by the primary chain wear.