Moving on from the prototype and have been able to capture additional learning:
1) Two screws instead of four, this reduces milling complexity and frankly ease of operation
2) Looking at brass screws for fun, most likely will go back to steel or black plastic
3) Reduced cell wall height from 3/8" to 1/4" which will make life much easier for removing keycaps
4) Updated lid thickness from 3/16" to 1/4" for easier removal from case and that thick aesthetic
To do list:
1) Find cheaper CNC milling quote for price breaks of 25, 50, 75, 100
2) Nail down hardware choice
3) Find foam insert supplier and quote