Congrats, flex; it's great to see a "build" that's actually BUILT as opposed to disabled. That thing should flick, stay hooked up, and do what a capable rider wants done!
The needle bearing swingarm may cause a little grief; in the XS650 frame the swingarm axle serves as a pinch bolt, and the sleeve around it ("inner bushing" in Yamaspeak) extends a few thou' past the swingarm pivot ends and butts against the thrust covers to provide thrust relief, allowing ~45 ftlbs of torque to be applied to the swingarm axle, tightening up the frame. If your setup has needle thrust washers, most of those won't take more than ~25 ftlbs. before they get unhappy (please don't ask how I found this out), and that leaves things a bit squirmy.
One cure (thanks, Dwayne Burge!) is to weld a piece of bar stock across the frame over the pivot. Being lazy, I went back to bronze plain bushings.