I think most people will agree that it's easier to re-cover a double- pan seat as opposed to the single pan variety. I picked up a single pan seat in poor shape and decided to try making an inner pan for it . An empty cereal box was used to make a template of the inner portion of the primary pan. It was then transferred to some 1/8" thick fiber board I had in the garage. It seems to have turned out alright. I use marine- grade black vinyl from the local fabric store--- it's durable and cheap.I don't have the knowledge and expertise to recover a seat like the factory did. The inner pan helps hold the material tight and looks a heck of a lot neater than seeing all that folded over material.