(My reply was sent a second after Kai's)
Hello Seth,
What strikes me as unusual, to put it gently, is that you have the intention to copy a sophisticated, popular capsule, which is already copied by half a dozen manufacturers, and is in development by another had a dozen, or more, but you do not seem to want to invest time and money in a few samples, all of which you can find with a bit of energy and money- let's say, a Neumann-Berlin version, a Thiersch PVC, a Telefunken USA Mylar, a Flea, etc.?
I applaud your desire to deliver what may one day become the ultimate copy of them all; but wouldn't provision of a few samples you could measure, feel and observe, up close, with your own eyes, be the very minimum R+D effort into a reverse-engineered or otherwise "interpreted" M7? It sure is an essential aspect if you ever wish to get there.
Best of luck!
KH