Z500 Head Swap

I've got a neglected 1980 Z500 sitting in the shed that I'm hoping to get running again after sitting in the shed for the last two years.

The original problem was that she wouldn't start due to low compression in two cylinders, due to leaking valves. I've been given a compatible Z550 head with both cams, a few valves in it, but no shims/buckets. I've also ordered a new set of valve stem seals to reduce oil consumption as some are quite loose.

I'm hoping to put this together with the best valves from both heads by lapping/grinding the valves in as none of the local engineering shops will touch old bike heads and I can't really justify buying the equipment for such an old bike.

Would the Z550 head provide better power/torque from the engine, and which set of cams would be best to use in this case? I'm after a nice easy ride rather than top-end power. It's a road bike after all, not a racer.

Any other advice or ideas on doing this with minimal fuss?