Congratulations, you finally made it. I wish many troublefree kilometers with your new Bullet!
Alas. the seat. My intervertebral discs were on fire after the 30km test ride, I especially missed the opportunity to slide forwards and backwards.
Before you finally ged rid of it, try first to alter the adjustment of foodpegs and handlebar. Although only lilltle alterations are possible, it´s sometimes the case that these make the decisive difference between sore back and happy riding ever after.
If this doesn´t work, Hitchcock´s in Britain offers a variety of seats and benches, and so does Nfieldgear with a lillte mark up due to shipping costs. You should be able to find an appropriate one, however it´s not easy to tell after 10 minutes if a seat will be comfortable after 300kms aswell. Maybe it´s a good idea to look for a dealer with some demo bikes with different seats to have the opportunity to test them.