I did my 54 with the burlap on the springs then one layer of batting. On the seat I added a 1 inch layer of foam I got from a local shop. Don’t add anything extra to the back. I originally added the foam there too. The result was sitting on the edge of the seat so I took it apart and took the foam out and it’s ok. I used hog rings on everything and like that I know it won’t come apart in my lifetime.
1954 Chevy 3100 One problem solved doesn’t seem to shorten the list Montgomery, AL In Project Journals