Is that a real ? or talking out the rear for a blog?
You aren't supposed to donate your 24" necklaced short hose in an OOA emergency. The exception is, if its in standard length 32" or longer - this is acceptable standard. It has to reach your buddy. A short hose isn't even longer than an arm & leaves you too close to your buddy, can be dangerous for both. You can necklace a standard length hose & remedy your short configuration if you choose to, if you are worried, about donating your necklace. Buddy always gets the longhose though. In your config, that's the one supposed to be clipped to your D-ring - the longer hose. He'll just have to wait for you to unclip, which is something you have to become comfortable with & the reason why there are reg switches in independent twins, by unsnapping.
How do you not have sidemount training, with -1,000 dives but are on doubles? ZERO, the profile pic shows you carrying a bottle? All you have to do is take-off your tanks & bands, clip one on each side & go diving. Necklace the left & clip-on the right in standard lengths. You can use any BCD, with D-rings & mount in-water, so you don't feel the weight.
Gas management, switching every 200 psi is too many times, sums like 10-13 switches, only a crazy psycho would switch that many times or more. You only need to generally switch 4-5 times max +/- & at the end, if you repeat for a perfect balanced END. Your gas management doesn't have to always be 1/3rds, it can be a set of 500 psi ascents, depending on depth & whether your entry/exit points depend on each other. You feel the tank lift & then you switch, its just one sensing method. Another is your internal biological diving clock. With experience, you sense your dive time switch. With 80s, every 500 psi is more realistic & you can also pick switch points, during your dive, like during NAV or use waypoints/objects/landmarks. If you switch using 1/3rds, your trim will suffer. It's O.K, can work but just a-little long. IOW, it just isn't ideal & inst. don't teach every 1,000 psi because of trim.
That's why, you can necklace a standard hose length, which comes first, before short hosing your config. In this case, you donate a standard length hose & again, remedy your issue. The other problem is, you aren't comfortable donating the clipped hose, which is the one, that's supposed to be handed out. That's a problem in your config & you aren't trained for it. It isn't supposed to be an easy to donate reg, like a necklace, where you just pull out or an OCTO in a BCD pocket/sleeve. This one requires 1 additional task. On IND twins, the long hose still has to be secured. However, you are right in, that you first let it dangle, it's actually acceptable & you can do it, upgrade to a boltsnap later or use a retractor or other plastic clip, even a hose router, whatever you have - eventually a boltsnap. By dangling it, it isn't optimal but it just has to be near your mouth or chest, accessible considering. You can even tuck it in your waist strap - this is another method for a time, when BCDs didn't have OCTO slevees/pockets, D-rings or BCD pockets.
Actually, with independent doubles, you always have redundancy, over a manifold. I'm not going in-to details but a diver can loose a ton of air or all of it, using manifolds & not have enough to even finish a proper ascent, much less a 1/3rds exit. With IND twins, the gas is always there for you, even if the other tank fails. You can extended range (XR), using air & nitrox - XR with NOX & bottom on air. You can even trimix on independents, while you can't on manifolds alone because you aren't supposed to separate gas. With IND twins, the gas is already separated, while gas is mixed, with a manifold - in traditional. The name of the game is optimal oxygen for the dive, the twin can achieve that. I will have lower nitrogen loading, XR & DECO gas, with independents.
You will just have to live with the fact that you aren't supposed to donate a 24" necklaced 2nd stage for OOA buddy emergencies & that the right long/longer hose has to be clipped, with a snapbolt. Yes, people are trained in that, during class. What you lack is training for independents, sidemount & carry - how you have 500-1000 dives, while still asking a basic question is mind boggling. For all those years, your config. & emergency plan was wrong.
I don't think it's a good idea to build doubles on deck or below deck on boat rides to a dive location. It doesn't make sense to me putting together parts on the ride out. You can just as easily clip-on a pony-40 or 80 cft, which gives instant doubles but since you have ZERO sidemount training, you won't like it, as you already discarded the style altogether. If a diver lacks sidemount training then that's, what he should train-on, the deficit. Don't get the wrong impression but you shouldn't be diving independents, switching regs or donating gas in emergencies. You gotta go back to, why it isn't a good idea to donate a short hose in an OOA emergency & why you aren't comfortable with any of the techniques. You need an actual real class, not a DIY.
