I have a sheet of 3 mm alloy checker plate that would be ideal that I don’t want it’s about 1500 x 1200 . I have plenty of pics of the one I had in my predator it was screw direct to the floor front and side and a bolt into the turn down on the gunnel ,it was always stable and never came loose in 14 yrs.
send me a pm and I will send you my number if you want it at a small cost . Matt