Seat rebuild question

The medallions are originals. I managed to break one of the three I have tried to take apart. I still have at least one more, possibly three more. The convertible only needs three so I'm good.

Covers are Legendary, but are now OLD. Bought nearly 20 years ago so I'm not sure that they'll fit as vinyl does shrink. They are still very pliable, though. Quality looks good. New foam looks good. Next up is my Barracuda and then the GTS. Hopefully, I'll be good at it by the third car. Gonna attempt the top on all three, as well.