Should have also added: overfilling in the glass is one thing, getting up to the airbox another. I'm sure suction is part of the problem, but the level was never high enough to create the airbox problem. I've had levels higher without the issue.
Who knows? The filter is dicey to line everything up, but the plug went into the filter hole through the 2 washers and screwed down easily. My drain plug was screwed up before I got it, but I think the problem is related to initial trial. I'll know better tomorrow when I run it with air box open so I can get a feel for the crankcase pressure. I don't know how an oil pressure problem could force oil up the tube. I think there's just lot's of splash and agitation and suction from the airbox would suck the splash up the tube, but the level wasn't high enough, hence my enigma. Understand, I always imagine the worst, and am relieved by the not so bad!!