You might be able to get by with the Quench that tight, but I would make sure every cylinder has the same quench. Production tolerances may give you less on some cylinders. I have run them as tight as .038 and had no trouble. Seen one set at .030, and you could read the part number of the piston on the cylinder head when they took it apart, ran for a season, didn't see any damage but it was set a .040 when it went back together.