To me it feels a bit like you're overcomplicating things.
I dive the air2 sometimes for shits and giggles and to annoy some of my strictly 'dir'-minded friends, also on a bp-wing single tank, but I've never actually needed to make any adjustments whatsoever to make it work properly. Just get a correct size hose, with a correct size corrugated that works for you and voila. You have no need for routing the hose as a loop through your left, you can still wear your stage/pony tank on the left side without issues.
I feel like the main reason for this wonky hose routing is the manifold you're using.
Your first stages are pointing completely outward, which is kinda a snag hazard, but the main issue is, this is making it basically impossible to properly route your lpi without having unnatural bends.
So now you have plenty of workarounds to do just to make it work, because you have some weird italian manifold that should honestly have gone out of production the second they introduced it imho.
Just buy a T or Y-valve for your 15l steel and you don't need to do weird stuff like this to make it work and you can keep your regulators the same on all setups.
I dive the air2 sometimes for shits and giggles and to annoy some of my strictly 'dir'-minded friends, also on a bp-wing single tank, but I've never actually needed to make any adjustments whatsoever to make it work properly. Just get a correct size hose, with a correct size corrugated that works for you and voila. You have no need for routing the hose as a loop through your left, you can still wear your stage/pony tank on the left side without issues.
I feel like the main reason for this wonky hose routing is the manifold you're using.
Your first stages are pointing completely outward, which is kinda a snag hazard, but the main issue is, this is making it basically impossible to properly route your lpi without having unnatural bends.
So now you have plenty of workarounds to do just to make it work, because you have some weird italian manifold that should honestly have gone out of production the second they introduced it imho.
Just buy a T or Y-valve for your 15l steel and you don't need to do weird stuff like this to make it work and you can keep your regulators the same on all setups.