I am still trying to find my cad file for building the box. So I can tell you my air space. I do remember that I put in 1 3/4 bags of polyfill.
I don't think anyone would pay for what I would charge. I built a ton of boxes but this was by far the hardest one.
I have no problems with over heating. The amp pocket goes to the back wall, so the heat can get out through the vents on the back wall. They do get hot, but have never turned off.
I raised the seat 1/4 inch.
It sounds normal, I don't now what you mean by mechanical noise
I have some more pic of while I was building it, if anyone want to see them I will scan them in.