I designed it to play a guitar like a baritone ukulele, but of course it can be in general useful.

I printed it with TPU and 5% infill, which works fine.

On ukuleles, I would recommend putting it to the bridge.
It should just be tight to the wood, otherwise it will snare.

For a Bass, it could be too slim, 5% infill is very flexible, but maybe the model needs to be adjusted then.