Metric and Imperial are a pain when used alone, when used in combination they become deadly as well as one standard polluting the other. General Motors introduced Metric and immediately introduced high tensile metric bolts for engines!
I design military and industrial equipment and using 2mm screws are a BIG mistake because of handling challenges, and the poor support they offer due to their small head sizes. We run vibration tests on our products and have experience in the choice of fastenings.
Three millimetre and 4mm would offer strength. There are so many holes
An acrylic panel of that size will also require support in the centre.
The pictures and drawings are not clear enough to determine whether the Acrylic ís molded or machined (drilled or punched) - the latter stressing the material.
Obviously, these Base Plates are not suitable for anything other than prototyping.
Ming suggested offering design files. Ì so, the option could be allowed to choose which holes should be drilled and which should be skipped.