My girlfriend wants a new bike and has outsourced this task to me. I ride a Giant Defy and think she would like a similar bike as we do a lot of riding together and I think she would do well on an endurance bike. I'm looking for a Liv Avail as the women's endurance model but she's between sizes at 5'8", with the Liv website listing M at 5'5" to 5'9" and L at 5'7" to 6'0". The Giant Defy is the men's equivalent and a M is listed as 5'7" to 5'11". She's fairly evenly proportioned as women go. Ideally I'd go to the giant dealer and she would ride all three to see which felt best, but there are no such dealers within driving distance that could accommodate this with demo bikes or out of inventory. Any recommendations as to a starting point in this process?