My set up is the same as post8 and I find it very convient not attempting to modify my tank bag. I have a camelback 70 inside of a factory made insulation bag. I have to lay in inside of the t.b. at an angle to get it to fit. Without such a bag , ice melts rather quickly, and the water heats up rather quickly. I find I drink much slower when this happens. If I were to buy another I'd get a much bigger bag/bladder. The mouth piece is a minor pita to use...but with practice I find I can get it in under the helmet and find my mouth while on the fly.