Gridfinity Ruler Holder w/ Thicker Slots

Remix of the excellent Ruler Holder by https://thangs.com/designer/atrimbletlr, with fewer, thicker slots to hold rulers up to 8mm in thickness.

While the model looks like some surfaces are missing, it prints fine (see the pictures) using Prusa Slicer and a Mk4 in PLA.

I'm a total newb, so feel free to tell me how this could be improved!