Use supports for the board holder. Don't scale anything, it's made to perfectly fit the board on the holder. I used normal UHU glue on the print bed but it's totally up to you (i still don't recommend you printing it without any glue. i know, it feels extremly weird to put glue on the bed but it comes off easily and don't break anything). To connect the boards together, i used solder with “flat head” and put it on 200°C. To mount it on wall, i used silicon tape. It's extremly strong and can damage your wall so if you need to detach the holder from wall, i recommend using heat gun or just hairdryer. This is my first model ever and was made in mattercontrol so that's why it's meh i guess :D. Enjoy!

!!!!!!WARNING!!!!!!

The other models (pokémon card stand, fingerboard stand, Dummy 13, etc.) aren't mine. Mine is just the shelf. (should i put the models URL here? i don't know). If anyone write me to put their name and model here in the desciption, i will happily put it here. (please don't be mad i am just lazy to find every single model :D)