@nate76, yes, 11 Mile CO.
This is all great advice, thank you all very much. I'm happy to hear that my upwind performance comparison of an NPW to a single skin is ill-founded. My son is on 157 skis, and has used mostly fixed-bridal foils in the 2.5m range on a bar with simple leash safety. He has done ground handling on larger kites with depower. The single-skin is really growing on me for the reasons you've all pointed out here - not to mention, yes, the lulls on the lake can suck the fun right out of it. Fighting with a kite to keep it in the air is exhausting, and I want him to enjoy his time out there more than anything.
Regarding the turbo bar, yes, it would be a complete rebuild.
I tried a friend's Pansh years ago and had issues that required a lot of tuning. That particular kite was not great out of the box, and I recall some tuning discussions online about them at the time, but this was several years ago. Ideally, I'd like to get him something that's going to fly controllably (and be safe) out of the box.