I made a second tray to mount equipment. In screws to the front of the wing opening and interlocks with the factory tray at its front end.
I'm planning to put two batteries and the air trap in the nose cone. These leaves plenty room on the two trays for the ECU, pump, receivers, Cortex, retract controller and CTU. I want to be clever with the wire routing to make maintenance easy. Its no fun to have to completely un-wire a fuselage just to pull one component out. That's what happened to be with my Rebel Hot: I need to take the pump out and ended up having to completely take the fuselage apart. Lesson learned!