During my '57 rebuild, I had occasion to use plastigauge to determine proper bearing fit on the crankshaft.
What the pkg looks like:
What the plastigauge looks like:
What the plastigauge looks like on the bearing journal--do not lube the journal or bearing insert.
Torque the bearings to spec with the plastigauge installed--do not turn the crankshaft.
Carefully remove the bearing cap(s) and this is what you should see (only clearer):
Next, use the package to measure the width of the compressed plastigauge.
Remove the plastigauge from the bearing journal, lube the bearing and journal torque to specs and you're finished.
As for the flat tappet cam and concern with enough ZDDP, I added this to the oil.