Im curious how this pans out for you. Ive been chasing slow to build and less than ideal oil pressure for some time now. I got a new (used) front cover, new oil pump, new main and rod bearings, new camshaft, oil cooler hot tanked when i got my radiator cleaned, new valve train/rods/lifters, new oil cooler lines, etc.
It takes about 8-10 seconds on a cold morning for the light to shut off and 15 total for it to reach 20psi on a cold start, idles at 10-15psi once hot. Warm starts are instant oil pressure but if it sits for more than a couple hours, its a couple seconds instead. My gauge wont read past 20psi at anything above 1500rpm but i suspect that is a fault with the oil filter sandwich adapter. Ive tried a mechanical and electronic oil pressure gauge with same results, electrical being them most responsive.
Curious how yours turns out and what the cause was.