Body Work - sub floor/floor pans

[orange150]

Body is slowly coming together on my CJ-5. I am about ready to redo my floor pans. With the drivetrain I'm running (351/C6/203-205 doubler) I am going to be making my own transmission tunnel, which of course will be much larger than the original. I was planning on making my own floor supports out of some 3/4"x2" square tubing but am now wondering if I should just use the replacement floor supports for an easier/cheaper solution and build the tunnel off of the replacements out of the square tubing?
These are the replacements:

 

[orange150]

Bringing this back on top. Still trying to decide if I am better off just replacing the floor up to the tranny tunnel with replacement floor pans or making my own. The only difference from stock will be the oversized tunnel.