Recovering the seats turned out to be pretty simple. I bought new seat covers from Moss and am happy with the way they fit.

After the old covers were removed, I discovered almost everything underneath was in bad shape. So I ended up replacing all the foam cushions along with the covers. I was originally planning on using the wooden bases for the cushions, but they were too brittle and I found a set on ebay that was less than new bases from Moss. The metal was very rusty but internally was in relatively good shape. There were a couple of holes that I decided not to worry about since it would all be hidden. I had the frames, the metal under the seat cushions, and the rails all powder coated and they turned out nice.

I've now put over 14000 miles on the car and they seem fine. The first long trip was a hot one and did result in a very hot back - not too unusual, though, with a leather seat and no A/C.