Hi!

 Designing a lightweight enclosure for a small UAV component, using 4 mm thick anodized aluminum sheets. For the assembly, I need to fasten this plate to a 3D-printed ABS bracket underneath, which acts as a support and needs to be removable. The bracket is tapped, and I’m trying to decide what screw size to use for the through-hole in the aluminum that allows solid clamping without too much play or risk of deforming the hole over repeated assemblies.

Would you size the hole just clearance for an M4, or would M3.5 make more sense considering the wall thickness and material combo? This will likely be assembled/disassembled a dozen times during maintenance.