I do appreciate your help. The 3 space mount has the same height as the 5 space mount.
I had hoped someone already knew of the part I was looking for, I wasn’t trying to put anyone on a hunt.
After looking for quite a while I’ve decided to change my objective.
Your idea of using the swing mounts is intriguing. I haven’t gotten to try out my newest approach yet. I will post here again as soon as I can.