Wicked, another triple! Be sure to check out yamaha-triples.org for pretty much all the info you'll ever need!
Sorry about the getoff, but welcome to DTT. The Triples are great and I am trying to find time to finish mine. Bike looks good so far.
yeah seat building is not as easy as it looks. But you learn alot by trying things. Gonna get heavy if you use to much body filler. Maybe just paint it with a couple coats of resin and see if that smooths it out first.