Update! I fired up the electrical last weekend and everything worked fine the first try. I was shocked! I should have extended the key switch from the battery end for ease of installation, but it's manageable. 5 strands of 14g wire, wrapped, makes for a pretty sturdy bundle to route along the frame.
After reading about options for the horn, I replaced the stock horn with a smaller unit and tucked it under the tank a bit. I cut and joined the gauge wiring with the handbars turned left .... fortunately the wiring has just enough slack when they're rotated right. Total rookie mistake.
Futzed around with the decomp lever for about half a day. Most of that was spent modifying the stock shift lever but once the pieces were ready, it went together smoothly enough. Not 100% sure how that'll work for me (my height, bike weight, odd location) but I'll give it a go before writing it off and doing something else.
Overall, I'm impressed with this kit. Between the build guides, videos and forum, this project is completely doable for someone like myself - zero experience, but plenty of time, patience and willingness to troubleshoot. I know a lot more about this baby than I did when I started!
Parts are off to paint next month. Still plenty of time before riding season - it's 30-degrees, foggy and super-slick out today. Guh.