Do you have a foam cutter or ... what did you use for the cutting?
Looks nice. I may do this instead of pluck foam if it's cost effective (using my current storage box). Then spray it with that rubberizing spray to make it black and a bit more solid.
I just used an Xacto knife to cut out the foam. It takes a little more effort than pluck foam, but I've found it to be much cheaper. The foam can be purchased in large quantities for relatively cheap.