We have a hopper that I think is a LIONEL. Its hook-and-loops sit much higher than our largely LGB rolling stock. We found wood shims of appropriate thickness, bought a couple screws that matched the diameter of the puka (hole) for the coupler mounting screws, tapped holes in the shims, screwed everything down, and added “jellybean delivery” to the Triple O’s freight services. This has worked for the relatively short trains that serve our version of Hawaii railroading of yesteryear. Had I been allowed to paint and weather this gondola for MOW service, the shims would have disappeared. Even as it is, they are hard to see.
I am not sure you want to use island engineering on an expensive locomotive, but it could be an easy and easily reversed way to make a transition car as you print a more permanent solution.