For the purists: hog rings were not used on 1954 seats. Little curved clips hold the material into grooves in the seat frame (Jim Carter sells the clips). Of course, most upholstery shops and restorers would now use hog rings (faster and easier).
RT1 gives good advice about using burlap, cotton-batting, and foam. I only used burlap, batting, and felt padding (as in the original) and I can still feel the springs (if I redo my seats, I will add another layer of felt and a layer of foam). I am fairly certain there is enough space/material to cover over these layers.
Tim
