I guess I'm stuck with gelling.

The engine starts and runs for at least 30 seconds even at -20, so there's nothing wrong that a block heater would fix.

I've put nearly a full quart of 911 in (except for spillage until I figured out I have to put something in the filler neck to open the valve). I put it in over a week ago and the vehicle has run successfully twice for at least six miles each and uphill to warm it up well. The fuel was originally treated with the diesel flow product in the white bottle made by the 911 folks. Wonder how much you need to use. I used the amount recommended for below 0.