The gauge shows what the relief valve says.
It's not the local pressure at each bearing, or an average.
Loose clearance insures that the pressure drop between the first and last bearings in a gallery is higher than a small clearance.
My conclusion: .004" is safer than too small, but stay away from the 0W20 stuff.

BTW: .001" clearance per inch of journal diameter was industry standard 100 years ago.