I used 3/8" (9mm) baltic birch and finished it with English Chestnut stain, then a clearcoat to seal it in. After making this project I’m really thinking about making a bunch of these to store all of my random supplies in. Adding text to any of the faces (to help identify the box) woudl be trivial and a nice way to keep everything organized.
I thought I might try creating some of these joints so experimented with clearances. A .002" clearance (slot .004" wider than the tab) gives me a nice tight fit that can probably be used without glue. A .003" clearance is a nice slip fit with room for glue. How does that line up with your design?
Selecting one of the tab cutouts, we find that it is geometry, not a rectangle with parameters which may be updated, so we need to recreate each such rectangle to allow for simple size adjustments:
Changing the thickness of stock can be envisioned by selecting each rectangle which represents the parts and insetting it by the desired stock thickness:
Then duplicate everything and drag it to the working area, select a part outline, and then shift click on a tab/dogbone outline so that it is the key object and Boolean subtract: