Tiny War Tank

I had a CL score [impulse buy] this weekend.  I picked up a tank, fender, and seat for $100.  The tank was primered and seemed to be repaired based on the magnet test.  When I got it home and sanded it, it became more ugly-duckling and less beautiful-swan.  It doesn't have any major dents, but it does have a few minor ones that need to be addressed.  I will probably make it work.  It would be a good candidate for the rusted look.

The seller didn't know what it came off since he bought someone else's street tracker project for parts.  I'm guessing a late 70s Yamaha DT250 or DT400.

 The purchase came with a fiberglass fender and seat.  The whole reason I pursued this was for the seat, but after seeing that it has a constant curve in the sea pan profile, I might not use it.

This is the shape I am after.  Flat for the first 80%, then an upsweep for the last 20%.  I guess I could make a new seat pan with the shape I want, then steal the cover and foam from this one.  That's a pretty dirt-bag option, but it would be cheap and easy.