KSH - go buy a rear mount cage. Put one water bottle in your normal cage and one behind. Drink the one in the normal position (on the seat tube), then switch it out for the one on the back. Should be easy to do if you get a rear mount with 2 holders, put the empty bottle in the empty holder and then take full one out and put it in the seat tube cage. Practice this on Friday. You'll be good. Rear mounts are not hard to manage. You'll be happy to have it later anyway for your long distance races in the future.