Well, you drive to the sandwich shop and then you go to the counter.....

Nah, jack up the car so the wheels spin, use the crayon to mark the center of the tires by rotating them holding the crayon to the center, lower the car, roll it back and forth a few times to get the suspension back into place, drive a nail partially into the 1"X 1", leaving enough room to stretch the tape, align the nail with one of the crayon marks, measure to the other crayon mark, move the rig to the other side of the tires, repeat and calculate the difference. You want between 1/8" - 1/4" toed IN. It's a rough gauge but certainly more accurate as the HF junk.