>>2570250I got bored and laid out your proposed rap rack. I also included a locker for the ATC and my proposed extra sling and 2 biners. You will also be using a locker for the prussik when it is in use, but it can be stored on its own locker or with the ATC. In all, I think you have too much gear for rappelling, but that’s a bonus and with more experience you will be able to pare your rack down a bit.
To count:
> 8 lockers> 2 120cm slings> 1 60cm sling> 1 ATC> 1 prussikYou could probably get away with less lockers, honestly. I hope this helps, and let me know if you make any adjustments and I’ll try to lay it out for you.