There has been discussion about the standard for 3 Rail coupler heights. I think the .688" height to center of the coupler is the standard. But you need a gauge. So I designed and printed one today. I think it will be a handy tool, especially for passenger cars.
I will see what needs to be done to get it added to the catalog in the next fiew days.
It has now been submitted to the catalog 10/5/2022