I don't think the turbo seals were leaking at all tbh. Looking at the engine in bits now, I'd say one or more of the cylinders that was lower on compression than I wanted, was allowing lots of blow-by, causing the oil control rings on the other cylinders to fail. What's odd, is that the car was still running and boosting, so perfectly, with all that smoke. Either way, with new pistons and rings and a freshly bored block, the problem should go away now.
That said, my oil pressure was always particularly high, confirmed even more when I fitted aftermarket gauges. My digital gauge only registers upto 120psi and it would hit that religiously when cold, but warmed up and on full boost it was still around 90+psi and on idle it was still over 50psi at all times, lol. So who knows, maybe the oil pressure being so high constantly, was in fact pushing oil out through the turbo seals, may not have had anything to do with crank case pressure at all. Some credence is leant to that too, by the fact that there is no visible damage to any of the rings and every piston looks to have been burning the same (Discolouration and markings all identical).
I'm switching to a different block and different heads with this rebuild, all of which will be properly machine and prepared, so fingers crossed, no more issues.
