I know the originals used a molded rear seat "bun" and cotton batting. For those that have restored a 1970 convertible seat, what did you use? If foam, 1" or 2" high density? A mix of high density and batting? I stripped and blasted my frames now it's time to recover.
Thank you in advance!

 

Typically i will just use Cotton felt batting over the top of Burlap and jute decking. I use 3 layers of cotton for the upper cushion and 4 layers for the rear.

If you really want to use foam, use it in the bottom- i use a 2" High Resilience / 50# (pink) foam in the lower cushion- 4-5" overlap on the sides and front tucked around into the springs, hoginged at the rear.
The foam makes for a nice firm seat & Taut cover- but its much more challenging than cotton to install as you have to compress the foam and the springs and stretch the cover to install.
I don't like to use foam in the rear upper cushion- I only use cotton. But if you do want to use foam there, it should be a softer foam than the bottom cushion.

hope this helps
Ben