I've set it up so I can take off the entire top.
First, I cut the forward top leading edge of the footbox down so the inside top cover piece will now fit flush against the inside of the 3/4" tube. I then tapped the 3/4" tube for button head screws. Now, my footboxes are a little different/weird looking than most. I've gone beyond the regular looking footbox. The angled pieces along the different edges of the footbox and held on by button head screws are actually covering two footboxes one inside the other with a layer of Pyrogel insulation in between. The angled pieces simply cover the insulation and give a finished look to the edges of the footbox. The outside footbox and angled pieces are mirrored stainless steel with the protective layer still on. None the less, that entire top piece is removable.
I have mounted my body to check for a proper fit on the footbox and other measurements. I also wanted to check to be sure I could remove the top piece without too much trouble. It is easy to remove with the body on. Also note the edge of the hood opening is able to fit down over the 3/4" tube without touching the aluminum top piece. Most will trim that edge of the fiberglass so it will not touch the aluminum and fully sit down onto the 3/4" tube.