I carry three bottles on me for most rides. One in the cage and two in my back pockets. When the one in the cage is empty I rotate a full one in. I carry the larger bottles (22 oz.??). This will usually last me around 50-60 miles depending on the temperature.
I never really thought about comfort, I guess I am just used to it. I do like a snugger jersey, otherwise the bottles flop around and hit you!
What is so uncomfortable?