Sharing another option for the bottom bumping is a small snip of window/door foam weather strip. Buy it in hardware store or dollar store in rolls. Adhesive is easy peel & stick to art back at rail contact. Probably just like your method, but I was out of tape. FI was doing Fall draft dyi, so I did have the window weather strip on a roll. I tried it. Really great cushion, easy stick, easy remove. Also cheaper than the cushioned crafts tape.
Great timing as this is the last part I have to do in our new studio. Hubby (the one with the tools) wants to do some complicated deal with removable dowels on movable strips but really? Keep it simple silly!
Joyce, tell him not to do all that because it won’t be flexible and it will drive you crazy. The method I use has a proven track record of success. Your husband must have been an engineer - they can screw up anything!
I dig that you mention Bob; one of the top influences on my journey the last several years, and thank you for this and other solid advice. I feel blessed to have such brass tack guidance ! 🎨