Evening..... Well, from what I'm reading.... You are trying to build a reverse flow smoker... Your ideas are somewhat unconventional....
May I suggest you read a few threads in....
http://www.smokingmeatforums.com/f/201/reverse-flow....
In that RF forum, there are many proven builds that may meet your needs.....
The problem with unconventional builds is, "whether or not they will work", which is part of experimenting but..... you may end up with something you are not happy with and have to cut it apart and rebuild it at least once....
If you are up to that, go for it... our members are trying to direct you in a direction, that you will be successful...
I'm all for being different.... been there, and have had limited success..... Now I try to find a few proven aspects of my builds and extrapolate on those proven ideas.... Still, my designs are different and at times even work....
Everyone here takes pride in helping someone build the best smoker in their town,... or at least their street, so folks OOOOOOO and AHHHHH over it.... request you to cook some ribs for them when you fire it up.... wander over when they smell smoke just to OOGLE it...
Dave