Well, my Pyramid bearings came in. I set the unwelded stem, bearings and all in the neck and adjusted to where everything would work. Disassembled, with the lower bearing in place for a welding guide, and proceeded to my farmer friend for the weld.
I scratched a mark in the lower tree around the recessed stem( Aussies were right), then removed the lower bearing, reset the stem to the mark and welded away.
Got her home and reset the lower bearing using the stock 650 lower dust seal, flipped. Good contact. Also used one of the stock lower races to take up some slack in the lower neck. Bearings are perfect with this fit.
Starting to put it all back together now. Found that using the stock headlamp ears- I had to use a couple more rubber spacers to snug them up, no biggee. Also it looks like a bit of grinding needs to be done where the front brake line attaches to the lower tree. The 750 lower tree is a bit wider than the 650 and some metal needs to come off for a comfortable fit for the line.
I'll have to post some pics.