I'm mostly posting this so I have it on my account, there is a major issue when printing from the default orientation. See more info below.
I wanted to move my filament spool holder to just sit on my bench top next to my printer. I used the headphone stand as a base and made it so you can screw in the stock metal bracket using the stock screws (without the T-nuts, screws right into the plastic). I printed at .28mm layer height, 20% infill and 4 walls and it's plenty strong to hold a 1kg spool. The .28mm layer height isn't super pretty, if you want a cleaner look drop that down but I wanted it fast.
If you actually want to print this you need to lower it into the build plate 1-2mm. If you look at your first couple layers at the default orientation in your slicer preview you will notice that it doesn't actually print the whole first layer, it thinks a bunch of the bottom is a bridge printed on layer 2, 3 etc. By lowering the whole thing a couple mm's into the buildplate in your slicer you eliminate this issue. Sorry I'm having a real hard time figuring out how to fix this issue in Tinkercad so this was my workaround.