-22 degrees for the low this Wednesday

If the A/F is reasonably fresh (a few years old) and properly mixed like it sounds with your hydrometer readings, it ought to be fine. I can recall having my Saab outside in OH in -24F blizzard conditions years ago... nary an issue. And I had a rental car in the high mtns of central ID 2 winters back when it was getting down to -35 to -40 F for several nights in a row. Never started the car, and it was fine when we left at a torrid -20F LOL