Not perfect but it looks decent in my opinion - to be perfect it would be made out of one piece of molded vinyl and the pleats would be pressed in with heat rather than sewn in. The secret is to poke the cord welt into the lip which takes the vinyl into the lip with it. Poking the vinyl could result in puncturing it and if that happens you get to start all over again.
Stew another fine job. My take, If somehow someway one was to discover a time capsule that held let's say a 900 and it was perfect except for the seat cover then maybe I'd concede that an heat pressed pleated one would be only more original and therefore letter correct. My thoughts are yours are made from much better material. The sewn pleats are MUCH NICER looking than the pressed in shiny vinyl original ones, hands down ,no contest. My bet is you ask Brian on any of his meticulously restored pieces that a 29Chev seat is the perfect finishing touch he'll agree, his units are as good as new and probably better looking when he's done based on his attention to detail, your seats match that attention to detail, already know Rick feels the same way about your seat on his beautiful 1000. Bet the fan club includes all your customers. I know this , I own several, every one of them is the nicest thing on the tractor, just the facts buddy. As long as you continue to put thread thru the needle, shear the fabric and cut the foam, I'm sending my pieces to you. You're talented , I'm a fan , big fan. Thanks again.