the engine should be warmed up before hand so the valves train/seals are oiled and there's a normal oil film on the cylinders - should be done w/ the choke full out or carb blocked - test with ALL plugs out, not in, so you get max cranking speed - don't add any oil to the cylinders until you check each, then add oil the minute before you retest any low ones - as said, good would be 120 +/- 10%, all 6 fairly even around 90-100 is ok, but if any are 20 or more less than the rest you got problems
Bill