Drat, I meant to check the suspension setting but forgot. It was pretty chaotic there with a good 30+ people all over that car
Hopefully someone else took note of the setting. For now, I have to assume it was the default, which I understand to be "low." I didn't see anyone playing with the suspension height the whole time I was there.
18" out was indeed from the side panel of the driver door.
Also, I'd note that the rails of my garage door are at the standard 88" high, but because of the way the falcon wing doors slope down that shouldn't be the limiting factor. The intersection point will be a good foot or more in from the rails. Because the garage door sits an inch up in the track on its rollers, that gives me (and hopefully others) a tiny bit of extra room.