on scale of 1-10, how hard is to build a custom leather seat?

I def. want a new seat for my street triple cafe style project. I'm fairly handy with a wrench, wood, light metal work etc. But I have never worked with leather or foam. I was thinking of getting an extra seat from ebay to tear down and rebuild my own design/profile.​the only two aftermarket seats for the st3r are the triumph comfort seat (too high inseam) and the $500 sargent (which stops nuts from pressing on the tank). neither have the style I'm looking for, I like the Roland bmw nine T seat for example. via /r/CafeRacers https://www.reddit.com/r/CafeRacers/comments/bo62v5/on_scale_of_110_how_hard_is_to_build_a_custom/?utm_source=ifttt