Kind of off topic - but - is there any draw backs in running a skid plate under the whole cab of the truck like the stadium trucks? The only thing I can think of would be that the skid plate would get very hot from the exhaust header/pipe being real close. Anything else?
You may beat me in the flats, but watch out in the whoops! ! !
If you think you might use it a lot I'd recommend steel. Not just any steel, but something like AR, T-1, Core-10, or Ten-X. All of these are high strength, low alloy steels. Tough alloys with carbon contents in the same range as 'mild' steel so it welds like mild. AR and T-1 are commonly used for the sides of gravel conveyor belts in quarries. You could likely go down to 10 gauge (~.135") then. I'll leave the relative weight calcs up to you.
In aluminum I would not consider any alloy lower than a 6000 series, unless it's 2024.
"Teach you all I know and you're still stupid"
-- Howdy Lee