The LBS's I checked out when looking for a bike all let me take the bike out for as long as I wanted. I spent at least 30 minutes on each bike if not more. That way I could really see how it felt. I'm glad I did. One bike that I really liked and "thought" was a good fit was horrible when I tried standing climbs--it just felt wobbly. I think the frame was too small and I didn't get good balance when standing. So ride it around, and do all the things you do on a bike. They shouldn't care about the time, unless it's almost closing time.
Good luck. Try lots of bikes!
Whoever said last man standing wins never asked a girl to play!