I put together the two howitzers that I got after seeing this thread. I like the way they look with the limber attached, but as jini5 pointed out, that means one canon per flat car. I was going to put them on Menards 14” flats, but the car looked too big for the canon. So, I replaced home-made pipe loads on some MTH flats with the howitzers.
I have to say that I was not impressed with the Atlantis kits. Maybe I’ve been spoiled by Atlas O and Tamiya, but the Atlantis kits seemed to have imprecise fit between some of the parts, too much flash on delicate parts and some instructions that I found questionable.