I would say that the B17 is narrower, suited more for a road bike than a hybrid (I bought it for my Trek Verve 2 which is a very upright hybrid and then found out that for the tail pain in longer distances I prefer a less upright position (very much less, so I got a new stem for my Verve 2) and for the burning sensation (developed at longer distance riding -20+ mi-) a saddle with no padding). Then I found that I need a drop bar bike for the pins and needles in my fingers and ended up with the B17 on the Novara Randonee.

The Randonee's saddle lives on the Trek, happily, as it is my short distance, 'round town bike.

Get the B67 if you think you will keep the upright stance. Get the B17 if you recognize any of the other symptoms I described above.

Keep in mind, the tailbone pain comes from being upright for some distance and requires you to rotate your pelvis forward to a more aggressive stance.