Try closing up the plug gap to .025
Small I know....but it's just testing.
The only way to know if the rings are seated or going to seat at all is with a engine dyno OR leak down tester.
everything else is basically a guess at best.
My best guess, your 20w oil or washed down cylinders aren't a problem to worry about right now. To wash down a hole tales enough fuel you would nearly see it dripping from the exhaust pipes.
You haven't yet said anything about how the bores were prepped or what ring your using. Based on all you have said, I don't have anything to suggest washed down walls or oil problems. I know your reaching for a problem, but I don't think this is where to concentrate your efforts.
I suspect, you have two problems. The first is a slight over fueling problem AND a ignition problem failing to start the burn consistently, or completely, as in it may begin to burn but blows itself out leaving traces of fuel in the exhaust. That is why a new set of plugs and closing up the gaps are my suggestions. The smaller gap is easier to jump for the ignition system.
Leaving the timing at 36 locked is fine for now as its eliminates a variable, play with it later.
On a street application you want to pump to begin at throttle application and end as soon as the booster begin to come in.
35's are too big, 31's should be plenty, you just need to get the timing correct with the pump cams. This also assumes good healthy pump shots. Ones that fire a solid stream across the throttle bore and hit the booster hard enough to break up the stream into smaller droplets is ideal.
What color pump cams and what holes? Eric already asked.....It's important.