I am glad that we decided on the smaller O2 tank: the 33CF tank just barely fits. I planned to mount it transversely behind the aft baggage compartment and ahead of the bell crank. The tank is 7"; we have 7.25" of space.
I puzzeled for a while on how to mount the tank. I finally decided to use two 1" aluminum angles perpendicular to the floor supports. I started with 18" brackets. After cutting them, I decided that they didn't need to be that long as the valve end of the tank is narrow. So, I cut them down. After mounting them, I realized that there was still excess material, so I cut some more off. At least I got some aerobics using the hack saw!
I bolted up the system about 10 times before I got the fit right, but it looks pretty good. The tank is as far aft as practical and is well secured.
