just an aside on the gas tank plate thing, got under the vehicle again a couple days ago, taking more detailed measurements and another look around. Gonna be a little odd, but still serviceable as a 'second skin' for the tank. Prime issue is that the rear control arm mount / pivot is at about the halfway point on the 5' long tank. So my idea of mounting the plate to the frame rail winds up unsupported on the rear half. But my design is shaping up with 3/4" square tubing on the inboard edge, fastened to the tank saddle strap bolts as a sort of hanging ladder bar. That's version A. Version B is still a flat sheet with a semi-complex set of bends so the plate is just sandwiched between the tank and the saddle straps and has <1" of standoff from the tank itself. If any. Problem being the bottom of the poly tank is about flush with the bottom of the frame rail. Anything hanging lower is going to hang up before the frame rail and since it isn't being designed as a proper vehicle-weight-supporting skid plate, that's a real design problem. So installed that way the plate would probably be configured to fit flat against the bottom of the tank.
So I'm still exploring ideas basically, while trying to find some 3/16" aluminum plate that doesn't cost $400+ for a 4'x8' sheet.
I'm also looking to see if it is possible to mount a second set of saddle straps over the existing. It LOOKS possible. If it is it would make it a lot easier to install, than wrasslin' with that big tank and taking its straps off, both at the same time. Can't figure how to support the tank while trying ot take off both straps and get a plate in place. Maybe just drive it empty and use bailing wire to support it fore and aft while a plate is put in place.
/slow as a glacier, like usual, but I get there eventually...