The roadster seat on the speedmaster is really for one person and a pillion rider only for a very short distance. If you are going to be going two up a lot, there are quite a few options. from the Butty Buddy to a solo seat with with a larger pillion (America seat), or any number of customs. I bought a solo seat, had it made more comfortable from Greatdayride.com and bought a new style Pillion from a friend who was never going to use it. I know several people have the touring seat and really seem to like it.
Cheers and congrats on the new bike.

~Brent