I kept knocking off the regular hooks when taking something of so I made this version where you use an 8mm bar from an old 3D printer to link multiple together.

Printing

I've printed them with regular PLA, 3 wall layers and an infill of 25% and I haven't had any problems so far.

Remixing

The model was made with OnShape and should be available to all https://cad.onshape.com/documents/5d6f040f905bc86da2ecab88/w/341c4a905c907bbc0980aabd/e/f874c125019eedc31f4fb3e9

The cleat configuration is in the first tab (on the bottom), the settings per model are in the part studio itself in a folder called variables.