Looking for some advise on flat beds / cab and chassis

I have an Aluma bed on a F350 cab and chassis model. Light and simple aluminum bed.

1. Bed is just long enough for the skirt to clear the end of the frame rails.

2. Too tall is sticking up or out beyond the cab or roof. Wind noise when unloaded.

3. I use Fastguns - short model - tied to the rub rail on the bed. Rubber mat under the camper. My camper is a pickup model. I have some boxes that sit on the bed under the wings.