It’s a thankless task at the best of times Mark. I’m actually going thro something very similar at the moment. Very few actually grasp the complexity at the best of times.
Quite simply because they only work in 2d.
I had two pieces of bookmatched magnum delivered and they should have been reflected patterns, you know how.
Instead they were identical.
I called the designer and explained the problem (3 week lead time for more). I kid you not, she said "why can't you just rotate one of them?"
I had to get her to draw on a piece of paper (over the phone) for her to understand what I meant...
"oh yeah..." she says eventually.
As for returns inside niches... I've stopped trying to explain that one. Now I just keep my offcuts and get on with it....