I could only imagine the frustration, SUCKS to hear it went sour again. I’d be thinking of lighting and no fire hose atm myself. If it clears up in a few minutes after starting it’s probably not ring seal, I’d be leaning towards coolant in a cylinder. Run it until exhaust is clear, shut it down, immediately vent any pressure that may have built in the intercooler and engine coolant over flow tanks, leave the caps cracked until the car cools off again. Close caps and start it again and see if there’s a difference in start up smoke or not. If it’s gone your onto something, if not next I’d try fuel. Again, start up let run until no smoke, shut down, vent fuel pressure, either via a schrader valve on a rail or pop off the fuel line from the rail, just be sure to cool off the exhaust manifold first with some water. Let sit 1/2 Hr or so and start again looking for a difference. If none then I’d be suspecting oil from a valve guide as next culprit but seeing such is tough and would require removing the SC after a run and sit time and looking for a wet intake valve top.
You use studs or stock bolts on the heads?