Here is a guy with the type of burner grate I think works best. If the frame "box" is smaller than your pot, the grate should be higher than the frame rails to allow the flame to spread out evenly. His burner shields could probably use some venting notches. He lives near a town where I used to duck hunt. Nothing but working ranches around there. You can always count on folks from those parts to make practical things. Something the rest of us "dudes" could learn from.