Trouble shooting low oil pressure

[Porter Gieske]

Howdy folks-  (1982 R100RS)
Its me again, I will start out by saying that my electrical woes have been solved- with a new alternator rotor, and regulator, I am now seeing nice charging power.  And, my carbs are now tuned, so thanks again for the tips and tricks there.  I am trying to get to riding this moto, but I have one final issue, and that is low oil pressure, especially when the motor and oil has warmed.
I have the harbor freight pressure gauge, and an m12 adapter from McMaster to make testing happen, and, I am starting the bike from cold, and seeing 40psi at 1500rpm.  That lifts to 80psi at 2500rpm, and then lower values as the oil warms itself up.  I am hoping for values more like 90psi to 115 when revved, that should trigger the relief valve to open.
I have removed both side valve covers to inspect the oil flow at the rocker arms, I pull the plugs, ground them out on the fins and run the starter at 10 second intervals.  I see small weeping on the left, less so on the right.  There was plenty of oil in the covers from running it at idle.  Oil level is at the max mark on the dipstick, oil is brand new.
I actually have a second pressure gauge, because I didn’t trust it at first, and it reads basically the same as the HF one.  I started testing oil pressure because I was getting intermittent warning lights on my dash from the oil switch, which led to me to see what the values were.

What I have done:
Drained the oil, replaced the oil pan gasket and cleaned off the surfaces first, checked the sump, replaced the gasket under the sump and torqued the bolts.  I put the pan back on, tightening the bolts in a cross pattern, and stepping up to the torque in stages.  I saw no gouges in the pan surface, and I scrubbed them clean of previous gasket material.
I then moved to the oil cooler area - 
I pulled the filter out and inspected it - no obvious clues there, it is brand new, as are the o rings and gasket.  I am using this math for the gap in the shoulder of the filter housing - average depth is 3mm, I am using the back paper gasket, which adds 0.5mm to the total depth.  I am using 2 shims, each 0.3mm thick, and the O ring is of course 4mm thick.  This means that the o ring is under compression.  The black o ring was found to be in its groove, not pinched.
I even inspected the high pressure relief valve in the back wall of the filter housing.  Its a ball bearing on a spring that can get clogged or remain open.  I used a sharpened wooden dowel to reach it, and I was able to depress the ball and feel it spring back into place.  
The last place to inspect is the breather valve.  It requires the removal of the timing cover, which means all of the stuff on the front of the cover needs to be removed.  Its a deep dive, not hard, but time consuming.  

Oil pump details - yes, I replaced the oil pump inner and outer rotor with new parts.  I replaced the o ring under that cover.  This model year uses machined flat surfaces on the camshaft and not a woodruff let to hold the inner rotor.  Fortunately for me, Brook Reams’s videos on YouTube are perfect for me to follow, as it is the same model.  The fact that I am seeing some oil pressure tells me that the oil pump itself is probably not broken nor installed incorrectly.  It would be another huge task to inspect that area, as it is under the clutch assembly.

I pause here for advice on anything that I might have overlooked.  Any tips on recognizing oil pressure leaks is welcomed.

thanks
Porter