Couple 46rh questions

You need to put something back in there though, because of the torsion bars holding up the front end. You have to have something in there. Otherwise some 18 gage floor pan is all that's holding the stubs of crossmember where the torsion bars are.
I will. I have 3/16 ga strap I’m going to use. At least two layers with a gap in between each layer. The bottom strap I’m going to form to overlap along the bottom of the torsion bar crossmember all the way to the torsion bars. The top strap I plan to peel back some of the floor and weld it to the top of the crossmember for extra strength