Maybe I will have to do some yard sales looking for a chair. I need a seat badly. Been sitting on a loose pad and and I really need more back support. Old bad back,, I have a strap, but I need more than it provides.
What did you attach the foam with, like liquid nails or some such thing?
If it were me, I add more slats. That area gets a lot, probably the most abuse of anywhere else. Getting in and out, stepping down with grime on your feet, and I would think, I am a novice so don't put much in what I say, but I would think it adds strength to the structure also. One other thing I think you will want is footrests. There are discussions on this forum of cheap, easy ways to make them or get them through Jeff's store. They are much more difficult to add after the ship is skinned.