Stupid questions from an old aerospace guy quite familiar with machining processes: Is the thickness of the CAD that critical that it requires post application machining? I suspect the answer is "yes", in that its thickness affects the rate of absorption. Do the thickness requirements vary across the part, i.e. a uniform thickness will not suffice?
I find it surprising that you were able to find anyone at all to post-machine CAD plated parts. That's generally a big no-no, as its considered highly toxic (even outside of the state of California...
). Not many machine shops would have the environmental controls necessary to contain all of the nasty by-products. The chips would be bad enough, but any vapors or gases generated would be the real concern.
Cool project, by the way. You get to work on some fun stuff - I'm envious.