I watched Alligator Bob from Antioch, Ill. do a seat when I worked for him. He foams the seat then he black marks the the way he wants the seat to look. He then cuts out pieces of fabric to follow the black marks he made. Then I took his sample cuts and traced them on the leather allowing for a 3/16 stitch. Most of the time predicated on if he was going to use an exotic skin he had three to four sample pieces to cut out of the leather to make the seat. If, you go to his web site alligatorbob.com. you will see the seats he makes. I hope this helps!