First test. I used mdf 10mm. I failed with the mirror part (they were the same, they shoudn’t, but now I know I will make them identical to avoid mistake like that). After the photo I made them ‘identical’ (manually) and I test the tension around the 25mm pipe (it works). It’s fast to do, you can adjust tension, it looks stiff enough, it’s a bit heavy, it’s cheap! It lacks some screws on the side to maintain both part (just a first test).
Mdf 16mm or plywood need some tests, too.
The U aluminium profile is 15x15mm. The pipe without glue or screw is already well maintained. Screws don’t touch the ‘ground’ (it’s close however).