Don't think you want steel brackets scratching your camper.
I did front guide by starting with 1/4" plywood covering about 2 feet of front of the bed. My camper needed front raised to clear truck roof lights and that's how it started. Cut to the shape of the bed it stays there even when I have the camper off. (helps in keeping other materials from dinging front of the bed as well)
Than I added a piece of 2x6 on front with taper on the top, that's where camper front bumper rest and additional pieces of 2x10 on the sides, with taper on the top and cut to leave less than 1/2" play for the camper floor.
That worked well on old truck and works even better on new one, where higher bed leaves me with no way to see how the camper sits on the bed.
I can see it about 6" before it hits the front of the bed, but final setting has to be done by feel only.
