This Skådis holder is made to hold screwdrivers and other tools that are basically straight with a thinner part and a thicker part. The customizer takes two arrays: One with the diameters of the holes, another with the space allocated above the hole. Measure your things below where they should rest and above, put the first value in the first array and the second value in the second array. This does not attempt to create multiple rows, nor does it check if the holes fit the number of rows.
The print is quite simple, no overhangs or complex parts.