Use 3 mm diameter screws. Min. 8-10 mm long for feet and top shelf, 15 mm for stacking. Feet are optional but I imagine they distribute the load a bit and it is easier to attach some protective felt.
3mf files for multiple sizes provided. From 75 mm width, depth and height to 200 mm in 25 mm increments. Feet add 1.6 mm to height.
In Fusion 360 “Combine 2” operation seems to break occationally when resizing parts, but it is limited to “Foot” which isn't a parametric part.
The author marked this model as their own original creation.