[hiccup]

I will look for photos but don't think I have any.  I did attach a random photo I had of another boat that did this.  This picture might have been my inspiration.  Essentially, I used mahogany strips, roughly 1" x 1" in cross section and thru-bolted these around the perimeter of the 'nook' (the inset area to be filled with the cushion), then laid a piece of plywood on top of these mahogany 'cleats', and the piece of foam went on top of that.  The foam and plywood were cut to the shape of the nook using a template that I made.  I also put a piano hinge in the center of the plywood to make it easier to store.