I agree with cages to protect the valves from banging against some thing hard. They are good especially for inverted twins or when penetrating really tight wrecks. This though hmmmmmmm........ Don’t know if it's just a gadget or if it is really useful?
I would rather see a hook with a handle placed under the upper band. This can be used until one transport the tanks. Just like a handle of a shovel with a hook on the end. Or some thing like a fish grappling hook. This would also give more ground clearance and can be used against sharks and whales
Re--strength of manifolds. I honestly can not give you a 100% straight answer. I had an OMS manifold that was built like a main battle tank. Never an issue with that. The new set that I got was armed with Dive right. When I picked them up they leaked. The store owner suspects that some one banged them against the metal rack. When we took the center post off and changed the o rings it still leaked and then we replaced the whole thing.
There's an article on immersed magazine on a bizarre case of manifold failure. The setup was fine at 232 bars but when the pressure dropped the isolator was not pressing as hard on the pillar valves and there was a failure. Quite interesting..... My opinion is to treat it good, so it teats you good. After all your life depends on that piece of metal.
Lawrence Debono
Lawrence