Thanks, Badger. If the 17.5-in is indeed too large (certainly possible), I will ask the guy at the LBS about trying a longer seatpost. When I was raising the seat, at one point I pulled the seatpost all the way out and it seemed pretty short to me, though I didn't actually measure it. The guy at the LBS seems really nice and helpful, so I'm not upset with them, just trying to get a fit I'm happy with.