[c6ae]

When gauging the mains in the car the weight of the crank could give a false reading. A folded piece of paper (about .006) used as a shim on an adjacent journal to lift the crank up will eliminate this error. I usually only undo only one or two main bearings at a time being extra cautious at the ends; otherwise damage to the seals could result.
I have found plastigage to be a very useful tool, and pretty darn accurate. It seems to take a fair amount of pressure to get a true reading, i.e. I retorque the caps. It certainly won’t ever replace micrometers and bore gauges, but it will give you a clue whether or not you need to tear it apart...