We left a gap on both the sides of the floor and the styrofoam pieces are resting on top of the rivets in between each channel so they are not touching the hull. We, or I should say, my dad kind of figured that water should be able to flow over the sides of the floor and under the styrofoam to the center and then back to the bilge area. I was going to put the styrofoam on the floor and call it a day but he said not to do that because we needed space under the styrofoam to let water flow.
Also, we are cutting small openings along the bottom of the angle frame. When we're done there should be several 1" gaps along the bottom of each side of the frame to allow water to flow under the side compartment frame and down over the sides of the floor.