I reused my hog clips, the new handful I scored for free from a Chevrolet dealer were too big and if you are patient removing them, you can re-use them
I replaced my seat pad element in 2 hours with a break for lunch. First attempt at upholestry work too. Take your time putting the leather back on the seat.
ALSO, be careful, use a hairdryer if poss, removing the old element from the cushion. You can tear your seat up. Another reason the dealer would charge over $400 for this job a kid could do.