Vintage Double Hose

Has Anybody Tried This Yet? - I saw some references to the CGA 540 connection on oxygen tanks and it looked like it was the same as the connections in a USD Manifold. So, I tried fitting them together and the connection looks like it would work.
- The first problem I see is that the gap between two tanks connected this way looks non existent. Skinnier tanks?

This could be a solution for divers who don't like the bushing conversions... Just leave the original valves on the tanks and connect them with the USD Manifold.

Several years ago I was given a set of double USN tanks set up that way.
Original hydro's 2-42, last 1-57.
Haven't done anything with them, sitting in the garage til I have some time.

I see potential for gas blending with that set up. Double 02 bottles connected with a transfil whip to scuba tank. I've been looking for a way to do this for awhile now.