Thanks for all the ideas. Miimura's idea might be what we end up doing. I already have a subpanel with critical circuits, that's manually switched and run off a portable gasoline generator during an outage. But there's only about 50A worth of circuits on it. So we'd have to move most of the others over to it, as my wife wants the AC and washer/dryer to work during an outage. We were out over 3 days with hurricane Michael this fall, and no being able to do a wash put her over the edge. Since everyone was out, the closest laundromat that had power had lines around the block. Well that, and having to go get more gasoline and refilling the tank in the middle of the night, etc.
I was just looking for an easy solution, and whole-house seemed the way to go until we hit this snag with the HPWC. Part of me is wondering if I'm getting a runaround, so I was hoping to find another Tesla owner that installed a whole-house generator with a HPWC to see if they had the same issue. I also sent a question in to Tesla.
As for generator, I was looking at 20kw, which is a 1L 2 cylinder engine - not quite a lawn mower engine. Heck the 16HP engine on my 7.5kw portable gen is way better built than a lawnmower's. And miimura is correct propane usage is a big factor (besides the extra $5000 the bigger gen would cost). I only have a 500 gal buried tank, which would last about 5 days at half load with the 20kw model, not including any I use for hot water or the furnace. The liquid cooled 25/30kw ones would drop that to 3 days. I was even considering dropping to a 16kw model just to squeeze out more time on the tank.