When I started with Eurorack I used a bamboo silverware tray with a couple of pieces of pine along the top and bottom edges inside to screw the modules into. I had a couple of blank panels next to my uZeus to (maybe?) help with cooling a bit.
To prevent getting sawdust in the modules or scratching them up, I marked the screw hole positions, drilled pilot holes, started and backed out the wood screws, then screwed the modules down… that was okay once, but moving modules was really tedious and I quickly decided to get TipTop Z-Rails instead.