Remix of the organizer here on Thingiverse
That model requires you to use slicer to have honeycomb infill but not cover top layer.
This remix densely packs 3mm shank compatible holes in a square-ish area, so you know what to expect and it should work with most slicers and bits won't fall over as they are snug in their place.
Including a tester piece, you could also make something similar with Meshmixer using plane cuts, print tester first and see if you'd like to print full sized model at %100 or %102 depending on how snug fit you prefer.
Note for Prusa Slicer users. If your default layer width is larger than your nozzle, it might try to skip some internal walls, try enabling thin wall detection or reducing extrusion width.
Supports are needed for pegboard mounts behind.
See my Instagram post for the video https://www.instagram.com/p/CK1NdsKrrnd
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