Hi mate, nice to hear that, the arduino mega shield v2.4 you designed was pretty good indeed. I tried to use it for the v2.0 one since it has similarities regarding header layout but I switched to fritzing arduino mega in order to make it fit correctly.
I did the other board parts as aesthetical as possible since I need it for my own university project. I couldn’t find the original .CAD files but doesn’t matter as I keep the grid spacing between them (except for the mega header connector).
As final opinnion, I have no idea about df board since I bought this shield from local store.