Since N scale roofwalks are too thick, I try to use the eaves height and work backward from that.
Okay. That's much different than what you've posted to this point.
I would like to clarify the following.
If you only see "H" instead of "EXH," use the "H" that is to the right of "EXW."
Your "EXH", is actually the height where the Extreme Width occurs. It won't help in any way figuring out the height of the car.
The bottom line is you need to be careful guessing using the height of the eaves listed on the car. As an example, the new run of Atlas Steel Rebuilts have a foot and a half difference in there respective "EH" data printed on the car.
Jason