Premade Seat brackets

I bought a set from Jegs..........non adjustable.
They were about as strong as aluminum foil.
Cheap galvanized steel , not even .060 thick.
Then I made my own.
Real Flintstone like......I bent the 90's over the lip of a utility trailer's top rail.
Two clamps and a big hammer.
Three corners welded to form a box like structure.
They are heavier than optimum........but I used .062 cold rolled and it is plenty sturdy.
You get a little idea from this.......