I just bought another water bottle holder the other day because, like your set-up, one is not enough!

I actually bought two by accident. there was miscommunication between me and the guy I bought it from but by the time i noticed it, it was too late to stop him. They aren't expensive so I just went with it. As it turns out this is a good thing because like you said, you need more than one bottle on these longer rides.

Where did your sister go while she was here?