Hi @johng,
This is really cool - thanks for sharing! 
This kind of idea has come up previously here, but in my imagining of it I was thinking of a single piece to serve as a slot for penetrators as well as a flange connection on either side.
I’m curious why you opted for the approach you took - was it mostly for penetrator accessibility (presumably they’re easier to install with such direct access), or were our existing flanges just available at a low enough cost that machining a larger composite part would have needlessly made your part more complex without saving much on cost? 