I finally finished of the auxiliary bus and flap relay panel cover. This project took a long time (and two attempts). I used the 1/4 turn fasteners that were allocated to the engine cowl oil access door (I will use Hartwell latches for that). I installed the microphone/headset jacks, the aux bus and flap relay then closed it all up to make sure everything fits back there. No problems, and I’m happy with the final result.