The stock Speedmaster seat is OK for very short rides around town and so on.
I kept mine for riding solo.
If you want to keep your passenger happy and in the saddle for more than 45 minutes, get the Triumph touring seat and add the sissy bar. It's really the only way to go for 2-up riding.
FYI, the wife is only like a size 4 or 5 (US). A wee little thing.
The sissy bar changes the look of the bike, but in a good way I think.
Good luck!
[ This message was edited by: Silverado57 on 2006-12-24 15:08 ]