RFruend -
I used the term "exposed height" since it is very close to the actual wall height that is not buried very deeply. It would take a very unusual situation and desire for absolute accuracy to change the relationship radically.
If there is a slope along the wall (longitudinal), the base of the wall can be stepped and more surgical detailed analysis can be done using the actual wall height lengths if you want to treat the soil retained as separate sections and think it can work for the site and soils.
Since all of the major systems were developed in the same market and many of the same engineers consulted for many systems if it was possible because of patent/information disclosure restrictions. That is the reason the major systems have slightly different product features, but essentially work the same in practice. - You could load a few semis with the reports and test results conducted.
I remember working with all of the major systems during the development, production problems and the first installations including seeing them delivered on a raft for an installation on a steep river valley.
Just rely on the product developers technical information/assistance, the staff support and then determine which systems are available near the project site and design accordingly. they have seen some very unique situations, having been involved in projects in more countries that I have visited (37 so far).
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.