Today I installed the FlyLED controller board and the light dimmer circuit board. These both went of the forward side of the sub panel. The mounting hardware protrudes through the sub panel, behind the vpower unit.
I uninstalled the shelf that holds the vpower box and transponder, to allow access to drill the mounting holes for both boards.
Dad made a template to mark the holes, and then we drilled them to the correct size. The plastic standoff pins for the FlyLED board worked nicely, the only tricky part was mounting the board, which I did by feel, since there’s no easy access.