And if the cylinder wasn't excessively worn before, it prolly will be after the 320.

I don't know too many people with hands calibrated well enough to sand something round and keep it that way. The plating is generally between .0025 and .004" deep so you don't have much room before you bare aluminum. Of course that's before the engine was run the first time, so an engine that started life with a slightly out of round cylinder would be seriously worn in several locations through the ring seating process. I do a lot of engines and only those that had carbon tracking down the cylinder walls need any kind of attention when replacing a ring. There are ways other than honing to perform the task that do not generate additional wear or a reduction in the plating depth.