My oil burning pig. Pics too!

Ima gonna take a guess here. Check your plenum floor and the underside of the carb baseplate. Wipe them gently with tissue paper. Actually blot them.Do this after a good, warm, run.If the blotted tissues come up oil-less, its not a reversion thing.
That leaves just three possibilities; Oil is passing through the seals or around the seals. Or the intake is leaking.
Since your valley is pretty much divorced from the runners, it's hard to imagine a valley leak, other than a flange gasket/milling mismatch. And that would require all 8 ports to be sucking oil.
Since you have adequate ventilation with breathers, I doubt the crankcase is forcing that oil through the seals.
So that kinda leaves ....around. Or perforation.
Well there is another possibility. If you spend a lot of time in engine-braking mode, with your 3% leakdown and gapless rings, I suppose it could be possible to pump that oil from off the cylinder walls up through the open intakes during the late closing intake period. This oil could condense in the intake and run down hill and end up there on the back of closed intakes,and it could run back into the cylinders after shut down. This would leave the runners slightly wet shortly after shutdown, but nearly dry, next morning. Hence the tissue-blot test.
I should mention that with the lack of a PCV, this diagnostic should actually be easier, since that system is not masking the symptoms with its own vapor return trail. And if you install a PCV system without solving this first, then that system will just end up putting the oil into the mufflers.
Have you performed a crankcase vacuum test, to prove that there is no vacuum in there? I know that you said the intake was tight as a drum,And it is very hard to imagine a gasket leak, but I have to ask.I also dont see any vacuum lines sourced off the intake; no booster, no vacuum advance, nada. Is that correct? And the rings were installed topside up, so they're scrapping oil down?And the oil return holes in the oil-ring grooves were open?
Anyway, I'm grasping.

BTW; 195psi and 3% are some really good numbers.