After mulling about your response all night, Rob, I have to agree with it. The tighter guides won't raise the oil pressure. So, the only possibility is that one of the seals came loose in some way. I can't see anything else related to the work you have done on the head other than a bad head gasket. This seems like a very remote possibility, but, if something went wrong on the gasket between one of the oil passages and the combustion chamber, the pressurized oil would flow right into the cylinder and burn with ease.

It's a remote possibility, but, I can't think of anything else.

At this rate of oil consumption, do you see any visible smoke in the exhaust when warm? I'm curious as to the point where visible oil smoke appears.

BTW, I removed my replacement head, and all parts, from the yokel yokel and shipped it to California via Fedex Ground. $60 and it will be there in four days.