Toe-in measurements

I am doing my alignment again tonight. It looks like my camber is off a bit. I have the Fast trak alignment setup. My question is, where are the toe-in measurements taken. If they are at the wheel you would get one measurement. If at the end of a 4 foot level, you would get another number (exaggerated example). Are you measuring across the tire or rim(with the Fast trak extensions)? At what height from the ground?
I watched the video instructions and it says a close to the tire as possible but at what height from the ground?

I hope that I am clear at what I am asking. Another way to look at it.
At 12 inches, 1 degree angle is .209 inches.
At 24 inches, 1 degree angle is .418 inches.

So,,, The higher you go on the tire, the longer the distance is and the greater the measurement would be for the same "angle" toe-in" I understand toe-in is measured as distance not angle, but it is relevant.