Well thanks for the input, I am not a wood worker nor do I have any interest in it, so I went with my own ideas. I have never grown stealth so my ideas come from more large scale growing. Carbon filter is my requirement as it should eliminate the smell at the source.
I also needed to extend the back panel the extra length due to my large light, so all the extra stuff for ventilation, not a big deal.
Not fully satisfied with my setup, but I can almost guarantee no smell during flowering, no light leaks.. now to take care of the noise from the stupid axial fan.