This is all I'll use.

DMR Hinged Clamp | Chain Reaction (chainreactioncycles.com)

I buy the 31.8 version and put a ShimaNO FD shim 28.6 to 31.8. That way I don't mar the tubing on my vintage steel bikes. They can also be added on the down tube facing toward the ground for a total of three bottles.

Carry that water Marine.