John, A few decades back, before we had today's metallurgy, it was common practice to replace all the piston rings without doing any thing to the cylinders except maybe removing the ring groove at the top of the bore. In order to keep the pistons from slapping in the cylinder the skirt of the piston would be either knurled or Kotherized, a process where by the piston skirt would be shot peened, to expand it. This was only done on the two sides parallel to the wrist pin. Some if not all new pistons were cam ground to provide a better fit also.
This method could prevent your pistons becoming useless. The rings would take care of the top and a little bit of egg shape will keep the skirt snug while providing clearance for lubrication.
Joe