I have been exploring options for HO scale display cases. I wish to mount several display cases on a wall to store a variety of engines and cars. I'm thinking about display cases that are approximately 36 inches wide and about 24 inches tall. I have looked at several commercially available HO scale display cases and considered building them myself. Can anyone offer experience with either purchased display cases or building such cases from scratch? In particular, I have noted that some cases put the shelves closer together while others provide more space for light and viewing purposes. I'm curious what shelf spacing will work best assuming the trains will be viewed while in the case.