I did what what red58 said.I used a 1966 door hinge and tightened it in the vise.I slipped the channel over the hinge edge and set a rivet,slid it down set another rivet.
To set the upper vent pivot,i used the flat surface of my vise.You might want to have someone hold the vent assembly when setting the pivot rivet.Take your time,they will turn out great.
I also used the rivet setting tool that you have.
Good luck !!

1951 3100 Chevrolet
1951 Chevrolet Suburban Carryall
Image
"A house is built with boards and beams. A home is built with love and dreams."
"Look deep before you leap !!!" / "Everything is Everything"
"If I say a mouse can pull a house, hitch him up"