these are a nice idea, and will help to explain to new players the idea behind spell slots.
I switched filament color when the numbers started printing to make them easier to read, and will have a different color combination for each spell level. I only bothered to do that on one side, knowing the bottom side would need more cleanup due to raft and support contact, if support were used. As it turns out, support wasn't an issue, but there will still need to be some cleanup (as can be seen in the second picture, where i separated one from the raft in order to demonstrate the back side).
It's a simple print, and I expect to get good use of them.