Ok, some real work...
I finalized the routing of all the air, fuel, and brake lines. Before clamping everything in place I covered the fuel and air lines with nylon braided sheathing similar to what's used on aircraft wiring.
I figured out where I wanted to put the floor cross-sill and cut holes for the body-bushings as can be seen in the last pic.
Then I shortened the cross-sill (only one side had to be cut bc the other side was already short to make room for the spare tire well), and notched it for the tank.
All of this will be blown apart again for POR-15'ing
Then I cut the temp ply-wood to fit and bolted it in.