I don't know. I think the most important thing for my sit-bones is the width and the "T" shaped seat-top. With the seat-post on the Kona Commutermobile the noise factor may be important. But I do like the springs, and Phil's bearing grease did take care of the noise once I moved my B67 to the Waterford.
Since I already have a B67, I think taking a risk on the B68 would be pretty ok. Anybody wanna subsidize my little experiment?
Ppppplleeeeeeezzzzz, someone buy my Serfas Niva.....
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson