Had a quick look at the rest of the wiring last night. Nothing obvious out of place. Power up resistor still resisting, replaced main fuse, cleaned connections at TPS and ECU. Since fixing the melted mess of stator/power wires near the rectifier, it does start better with no back fire or popping yet, and it hasn't threatened to stall again. At the recommendation of another friend, I may invest in some dyno time to play with the CO settings. I can check WOT and dial in the upper numbers, and also get some a/f data at steady cruise where it feels like it's not running smoothly. Or, I may just ride it. 2000km trip coming up, leaving Thursday. It does run really well under load Scooter, if it's accelerating at all, or high speed cruising like you mention, it's fine.