I ordered the foam for the cushions today. It's 5 inches thick and medium weight. When it comes in next week, I will take a pattern over to the upholstery shop and have the foam cut and covered with fiberfill.
The old cushions had a spring inner core but I don't think that's necessary.
I really want to have at least one couch done by the 16th of June...so I better make a plan!!!