so I think there's pros and cons to everything, including this.
In my experience one of the main reason everyone is using standard manifold valves is most of the original sidemount guys were using broken down doubles, super cheap to plug them, not so much to replace the valves.
Regarding the siding of the bottles, most of the mounting solutions are sided as well, so to make them universal you'd have to put the rigging inline with either the first stage or the valve knob, not a big deal, but it could put the knob and regulator at funky positions. If you think about loop bungees, they have to grab onto something on the outside edge to put rotational torque on the bottle, the bungee pulls from the outside against the tank rigging in the inside. This helps to keep the tank pretty stable against your body, the farther forward the bottom leash is, the more rotational tension is against the bungee since it is fighting the weight of the tank. For those valves to work, you'd have the first stage up against your body with the bungee over the valve knob per standard loop bungee routing.
If you didn't go this route and went with Razor/Dive Rite original/Hollis type bungees where you wrap it around the tank neck then it would work but for optimum SPG routing you either have the first stage face down for lollipop style routing, or straight up for SPG down the tank type routing. You can get away with first stage down and SPG's down with super thin/light or tied up SPG's, but it doesn't work so well when the first stage is against your body. This is more important in cave diving where the Bogaerts/Sorenson style hose routing mimics that of backmount so the turret has to be free on the left side to allow the hose to pivot to straight up and on the right where it is free to go forward during OOA type scenarios. Razor style inflator hose routing requires the fifth port to be pointing towards the center of your chest as well. With the above valves in either scenario you would have the regulators at a funky angle with the fifth port point straight down, so wouldn't work for Razor style hose routing, or you'd have the valve knobs pointing straight up or straight down, with up obviously not working well and down would mean having to change bungee style.
For rebreather bailout/stage/deco bottles where hose routing is less critical than with back gas, you can tie your SPG's up or use button gauges for bailout/deco, then these would be pretty nifty since they also don't require use of standard bungee attachments. You could have first stage up with the valve down and have it rotated into your chest a bit from the bungee and get creative with hose snaking, or first stage down and use the regular style bungees and wrap around the bottle, or ring bungees from Dive Rite all with great success.
I had thought about using these types of valves before and when talking to some other guys about them a few years ago, the current manifold style seemed to make better sense. Best thing though would be for you to try them if you have a few valves laying around and report back, don't know anyone who has actually done it, just theorized on it.
