The distance from the tradesman's bulkhead at the front of the Rolling Steel Tent to the back of the cargo compartment is 8 feet, 8 inches. But sheets of paneling are 8 feet long. That meant I needed to add a strip at the end of the roof panel when I did the buildout.
And so, in addition to the other small projects I've been doing lately, I took care of this. When one can't make a perfect butt seam, overlap them in a way that looks intentional. I made a new piece to go over the old add-on. And I cut it with a curved edge so it looks like a design element instead of a patch job. Here it is installed but not caulked and painted.