I just tried an experiment. I have a few pieces of what I think you call "031" track basic old O gauge that I have I took two of my 40 ft Atlas cars with body mount Kadees and coupled them and pulled and pushed through the curve. The couplers handled it just fine. Since they have 2 rail wheelsets, I had to miove them slowly or they would derail on the tubular track.
When pushing, depending on the car and how the couplers are mounted, the car corners may touch and cause issues. These were mounted with the face of the box even with the end of the car. Some Atlas cars have the box mounted to stick out about 1/8 inch which give more slack. But as it is, there is still a little slack in the coupler swing on 031 curves.
Since the Crown/Weaver reefers are 40ft cars (about 10 inches), you should have no trouble with body mount Kadeees on the 036 0r 042 curves. As I mentioned before, try a set as a test to see if you like it. By the way, they obviously won't line up to couple on curves.
