A lapped engine needs to stay tight, you don't want to have any excessive wear, it should only be just enough for a tight seal and then heat and work harden the surface to keep that fit. The piston may even grow a little during the heat cycling and give an even better seal. It is all in the link above.
Leaning out an extra 500 rpm per tank, never reaching a full 2-stroke, serves no purpose for a lapped engine without piston rings. It may well work on a ringed engine were the ring should seat against the cylinder while the spring action can take up wear, especially in dykes ringed engines.