Clear your front shoulder D-rings by getting rid of the bolt-snaps securing the blue tank shock cord/bungees: Use tri-glides instead and position them on the harness roughly 3cm or more under the front shoulder D-rings. Simply fit the bare end of the shock cord through the tri-glide/harness loop, tighten the tri-glide harness loop and secure bungee's end with a figure-eight stopper knot. Now you you easily adjust the tank bungees tension by tightening or loosening the stopper knot as needed. . .
Won't work for me - I like the bungee wrapped around the valve. I just don't have confidence in using the cylinder handle only - given some of the positions I can end up in traversing inside a wreck, especially given the silting/entanglement consequences if the cylinder should slip out and drop vertical.
The adjustable knot system you describe sounds useful for the initial sizing of the bungees, but afterwards, I'd like something a little more rugged holding it there. Again, thinking worst case scenarios... a knot can slip and drop the tank out of trim... which'd be bad juju in a silt-out exit. There's no risk of that with snaps and valve routing.
I've also seen hoses etc get tangled when forward swinging, and returning, the sidemount cylinders. Having the option to detach the bungee instantly, re-route, clean and re-attach the bungee seems to offer an advantage in that respect.
I also like the fact that the bungee itself is instantly detachable via boltsnap. It's another option available to escape from a trapped situation, especially one where a reverse is needed through a restriction.
Also get rid of that bolt-snap that's holding your inflator hose up and clipped-off to the left shoulder D-ring: all you need is a do-it-yourself
loop of shockcord to retain the inflator hose to your harness.
That's what I tried first. It doesn't free quickly enough if needed rapidly and is still prone to dropping out (issues in a silt-out exit). My current way of thinking is that a bottom-routed LPI poses a big issue if it slips free, as opposed to a top-routed (traditional BP&W) LPI, which won't pose that 'dangle' risk if it comes out of the bungee.
I can manipulate a bolt-snap by feel in zero viz easily, and I can cut it free if necessary. In return, I get solid confirmation that the LPI is always going to remain exactly where I need and expect it.
The idea & motivation again is to clear your shoulder D-rings of unnecessary/unessential bolt-snap clip-ons (especially those under extreme tension like tank bungee bolt-snap attachments above); these can cause jamming or make clipping/un-clipping other pieces of bolt-snap kit (i.g. reels, lights, stage bottles etc) very difficult. . .
Firstly, I won't be putting any reels onto the front d-rings.
Back-up light is in my thigh pocket now - I wasn't liking it on the chest for some of the penetrations being done. (If you remember the LCU - were getting down into the 'under-deck' through the little hatches).
The main issue I see is clutter with the stage cylinders - however, having the bungee and stage clipped onto the same d-ring isn't anything drastically more cluttered than a back-mounted diver clipping multiple stages off onto the same d-ring.
I've been considering adding additional 'off-set' d-rings concurrently with the regular ones... to provide a dedicated SM attachment point and preserving the front d-rings for stages only. I'd have to try them to see what sort of buggerence they may produce.
I like the way the Z-System LPI routes up along the shoulder strap under-arm. I'm thinking around solutions to ensure that mine does that (I'm short - so it doesn't). Running it through some bungees may be the answer.
