Sorry to get off topic but Chrisprols do you mind sharing your cad files and what type of material you are using? This is a great idea.
Don't ask me why but i never got the notification from the forum that I had a repply on this topic.
I don't have the files with me, next time I connect from home I'll sent them to you. However, the ones I'll be able to send you are not the ones for the wrench set. The ones I made were for my sockets, small ratchets and bit and pieces.
Regarding the material its plastazote. This is high density, heavy, foam. I advise to buy the one with black on the top and another color below. Black top : 5mm is great (less than 1/4"), then for the color below, just adjust with your drawer thickness (leave about 1/2" of space above).
For milling this material, here is the info I had read and I can share after some practice :
It's plastic, so mill fast speed with low rotation speed.
I set my Bosch Colt to the lowest speed (6000 rpm ?)
my feed rate was 1400 mm/min (55 in/min ?) (kind of the highest I ever tried !)
With my 1/2" straight bit (a router bit with 2 flutes) : steps down of 3~4mm (0.11 in).
leave about 5mm (1/4") minimum between 2 pockets so you have enough material to maintain some strength.