I have tried many different finishes for seats. My personal bikes all sit outside under motorcycle covers and I've had more than one seat rot away by trying different products to finish / protect the seats. I've had the most success with the following combination. I thoroughly coat the leather with neatsfoot oil two or three times before I tool the piece. Coating both sides of the leather. I let the neatsfoot oil dry completely then tool the seat. After all tooling and dyeing are complete I use Kiwi neutral shoe polish to finish the seat. Then I use Kiwi mink oil to condition after the seat has been on the bike for awhile. I try to apply mink oil often maybe every 6 weeks or so. After the mink oil is absorbed hit it with neutral shoe polish and it'll be nice and shiny like a new penny.