I just launched my Guillemot Expedition. I have carved a very comfortable minicell foam seat, but I used 4"x18"x24" for the exterior dimensions. My question is, How thin can I make the bottom of the seat before it becomes too thin, and how much should I scoop out of the thigh support section to give me a little additional room to install thigh braces/hooks? I 3/4 too much? Is 1/4 too thin or just right? The boat gains considerable stability by removing the seat and sitting on the floor. This lowers my center of gravity about 3/4 at the present time...Thanks for the input.