If memory serves me correct...the LGB, Bachman, USA trains...not sure of the Aristo trucks are usually the same height..when you mout them truck mounted.
As far as the MODERN trucks I have NO clue as I do not run modern stuff..but the archbar, bettendorf and Andrews that all three of the aformentioned manufacturers produce will/should all mate with KayDee
My suggestion is to get away from the various variables from manufacturer to manufacturer......KayDee truck mounted couplers..which look better.
I know for sure that the LGB, Bachmann, and USA, again not sure about Aristo trucks will match up with very little difference, even if there is a little you can use very small shims to get them to mate.
One of my standards on my RR are the use of KayDee..they look much better and there is never a problem with mating.
Purchase or make a coupler gauge, KayDee makes a very nice one I use it all the time...OR you can make one, again I prefurr a nicely manufactured one.
Bachmann couplers are WAYYY to big just like the Aristo ones.
IMHO
Bubba