Without getting into all the hose lengths thing, the only people who care about this are a few people on scubaboard. Only a few percentage of divers in the non-internet world dive the cave long hose rig in an open water dive.
The OP is incorrect anyways. The short hose is the primary and that is the one the donating divers KEEPS. This one is usually routed OVER the shoulder and has a short 24 inch hose
The "octapus" that will be donated is usually rigged on a longer 36 to 40 inch hose and that goes UNDER the arm and then is clipped by various means to the center chest area or can be hung on the neck with a break away strap. This is the reason most octapus units sold are bright green, orange etc on a yellow hose--from the factory.
If you buy a new AL, SP, whatever, it will come with a short hose primary for over the shoulder and a long(er) hose octapus that will be green, yellow, orange etc and usually on a yellow hose so that everybody can tell which regulator is to be the donated regulator--great idea--instead of all black which would be confusing to most divers.
Why is this so hard to understand? I mean, 98% of divers diver this way and are taught this way by every agency except for maybe DIR. This works better with most jacket, vest, so called back inflate BCs and work just fine with a BP/wing. A 40 inch hose will allow swimming and will allow an ascent. There is no cave. Most divers do not have any interest in cave and most have no buisness in a wreck. Their "universal" rig is just fine for their vacation or even advanced diving and it is less complicated than stuffing hoses and wrapping them around your neck and all of that, it is lighter and packs better.
The OPs history is incorrect. The donating diver is the diver in control, the OOA recieving diver is to follow the lead of the donating diver, if a simple and direct ascent can be made the donating diver is in physical contact with the OOAD, locked arms or whatever method was taught, and a direct ascent is made. This "physical" contact comes from the early days where most divers were water people who were Life Saving or WSI trained. The first thing a lifeguard does with a drowning victom--once the decision is made to make contact--is to gain control, this concept transferred to scuba when buddy breathing was the preferred method and double hose was all there was. The divers faced one another holding each other's harness and made an ascent switching the mouthpiece back and forth and rotating it. When the single hose became universal and octapus became the standard method of air sharing the only thing that changed was that buddy breathing was no longer required, the physical contact and "CONTROL" aspect remained to this day. The donating diver is the diver in command, the physical contact and eye contact not only reassures the OOA diver but it allows the donating diver to monitor the recieving divers condition, not possible with the recieving diver wandering around on the end of a a seven foot long hose out of arms reach.
The long hose method works great with highly trained technical/cave divers who have practiced over and over and who work in teams and they know one another and trust one another. This is not--NOT--the circumstance 98% of diving ocurrs in, the divers are not practiced, they are not 1,000 dive divers, they are not in an overhead, they may not know one another very well, they may not have practiced airsharing since they got "certified" and they cannot be trusted not to panic or bolt for the surface if left dangling on their own. This is standard life saving ettiquette and makes sense to 98% of the diving world.
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