Update:
Saturday I advanced the timing slightly. It ran crappy then heat seized.. I thought it was legit, will definitely do a more thorough test around the block the next time I experiment with timing!
I used the method where I make a mark of where the flywheel was at at TDC, then rotated it just a couple of millimeters to the right. No more than 2mms. Wasnt expecting it to be so sensitive. I'll be moving it a fraction of a mm from now on when Im messing with it.
The bike became unseized and ran like shit on my way to the HSBG festival, then wouldnt start up when I went to leave hours later. Yayyyy girlfriend with a zip car.
FYI, Scions fit mopeds just fine.