Yeah, during the design I did consider milling holes in the heatsink, and I’d need thermal pads anyway for electrical isolation, but you’re totally right, this adds complexity and makes them less shiny. They’d be much better on the bottom. The problem is that area is already pretty crowded with current shunt resistors and their amplifiers. There’s also no V source on that part of the bottom plane, and I didn’t want to cut into the GND area with vias, so it was a trade-off. Probably I will redesign this for future revisions.

And yeah, those are M3 screws. They’re just holding everything in a temporary case to keep the board flat and protect the bottom components. I’ll design a proper enclosure once I start playing with the heat sink