Precision machined head unit plates

I attempted to machine the head unit plates with hand tools, and found it challenging to stay within the 0.5mm tolerances.

I’m going to take a swing at precision machining them, either with a CNC mill or possibly a water jet.

If I make one, it’s not a significant additional effort to make several. If I made a batch, would anyone else be interested in parts?

I don’t have an immediate need for them, but I know there are other builders coming along, so it would be a good idea to make some extra sets if it saves money to do so.