Bruce,
The tank legs unscrew and the plate is flat. The black legs are only about 1/2" in diameter, so I put the legs and thin plastic base under the bed mattress. I can't tell they are there. The brass valve is about 10" long and it's easily stores away.
I was carrying two or more of the disposable bottles in an outside storage compartment, so the FlameKing bottles store there in the same manner.
Since I have two 20 pound bottles with my camper, it's easy to use one of them to refill when necessary.
If a person uses quite a few of the disposable bottles, it won't take long to pay for the kit.