Build a direct cooking unit; several doubts!!!

[Vulcanus]

Hello everyone

I need your help
I would like to build a Santa Maria Style Cooker similar to this cooker (thank you so much ggarner).

http://thesmokering.com/forum/viewtopic.php?t=41886&postdays=0&postorder=asc&start=0



There are two differences:
Probably I will build one large cooking grill, instead of two.
The walls is 16 or 20 inches tall

I have a doubt:
If the cooking grill never goes below the walls level, I weld the grill uprights outside the firebox and I weld around the grill perimeter an angle bar to place the grid resting on the walls
What do you think?
Can you help me?

Thanks to all.