If you use, or think you might want in the future to use KD couplers, be aware that they can be very sensitive to grade changes. Especially on scale length passenger cars or long freight cars like scale auto racks. Of course, once all wheels are on the grade, 1% or 10% hardly matters. It's the transition area that is a problem with scale couplers.
This was a problem for me and limited me to 1% risers.
