This is for an Interior Concepts cubicle system, where two wall panels meet. The brackets span 16mm gap, and assemble with M4 hex head bolts and nuts. 4x M4x30 and 4x nuts required. 

I used painted on supports for the hex nut cutouts in the brackets. Print the brackets with 3 perimeters and 100% infill, the shelf I used a box modifier around the countersunk holes to set infill to 100%, 3 permiters. The rest of the shelf I used 30% gyroid infill.

UPDATE 26DEC23: I got some heat-set inserts and soldering iron tips, and will be revising the mount components to use heat-set M4 inserts instead of M4x30 bolts with nuts and will update the model with those additional mounts later this week.