I get it that you're being sarcastic and poking a little fun at the GUE/UTD crowd, and to some extent it's deserved. It DOES all look a little odd on a 40' tropical reef. But it also comes down to standardization. Having become completely accustomed to it, the 7' hose just feels right in any environment, and I think I would find it unsettling to switch hose lengths depending on what kind of diving I'm doing. The idea of using the same hose, and donating gas the same way, whether I'm doing a real tech dive or a rec dive on a tropical reef, appeals to me. That whole muscle memory thing. My rig has basically the same "feel" regardless of the dive. I could extend the argument to include having a primary light on daylight dives, too. I personally draw the line there, and I do not take a can light or other primary light on a tropical reef dive--just a bungeed-up small light in case I might want to look at something. But I would be glad to argue in favor of doing so, as I can totally appreciate why some people might want to do that so that their rig has the same "feel" regardless of what kind of dive they are doing.
Yeah, that an OOG diver might strangle me with my own hose is a possible negative to the long-hose system that has been discussed to death over the years. Apparently there are many of us who believe the benefits outweigh that risk.
In another post, you mentioned something along the lines of standardization promoting laziness. I am TOTALLY lazy. The idea that I would not have to give a lot of thought to what gear to bring on any given dive was a major attraction to me of the sort of "system" diving that GUE advocates. To whatever extent is practical, I bring the same gear on every dive. I do use a checklist and am not lazy about checking off each item on that. You seem to be a tinkerer, constantly adjusting your gear, but I'm not. To each his own. I'd be more than happy to leave my gear in a certain configuration indefinitely if it were practical to use exactly the same gear on every dive.
I have to agree with
@lowviz. I do enjoy these discussions with you.
I am a tinkerer to an extent. Once I feel like I have things "just right", I quit tinkering. Scuba diving has a lot of parallels, in my mind, with my history in motorcycling. I am currently subsisting (just barely) with only one motorcycle. It's a 2005 model. I tinkered with it a lot, in the early days. Once I got it dialed in just right, I stopped tinkering with it. Now, I just ride it, and I haven't tinkered with it in years. It is truly the most fun bike I've ever ridden and it doesn't need any more tinkering (well, until I can afford a turbo for it...).
I'm still in the tinkering phase with almost all aspects of my scuba endeavors. I still feel like I don't even have basic trim "just right", so I continue to tinker with even basic things like my BP/W strap adjustments. Once I get things dialed in so that I can hover literally 100% motionless, I think I will stop tinkering with those parts of my "package". In the meantime, I'm really still very new to scuba, so I'm tinkering with a LOT.
But, there is another parallel here, in my mind: In motorcycles, I could find one bike that does everything I want and then dial it in and use it for everything. I would maximize my skill with that motorcycle. That is one approach - but not the one I use.
The alternative is to have different motorcycles for different purposes, use each one for its purpose, and develop complete proficiency with each. It takes longer, of course. But, in the end, it is possible to become completely proficient on each. And, in my opinion, becoming truly proficient on one kind of motorcycle actually enhances my proficiency on the others.
A specific example: on roadracing motorcycles (with which, I have almost 20 years experience), it is common for the gear shift pattern to be reversed from the gear shift pattern used on street bikes. On street bikes, you push down to go into 1st gear. On many race bikes, you pull up to go into 1st. To avoid mistakes and develop muscle memory, many people choose one way or the other and then set all their bikes up to be that way. If they race and ride on the street, a lot of people will keep their race bike with a street shift pattern, to avoid shifting the wrong way on the track (which could be disastrous). Others will convert their street bikes and race bikes to race pattern. In my 30 years of riding and almost 20 years of racing, I chose to walk both paths and become proficient with both. I was already proficient with street pattern when I started racing. I adopted race pattern shifting for my race bikes and still kept some street bikes with street pattern. It took some work at first to avoid blowing up a motor by running it up to redline and then downshifting by accident. But, I am now completely proficient with both techniques. I can ride anything, safely. I have muscle memory for shifting either way. It's simply a mindset I have to take on, when I get on a bike, that determines which muscle memories are "active", I suppose you could say.
Similarly, I feel like, in scuba, I could just adopt back mount doubles with a 7' hose and make that my single "bike" that I use for everything. But, I choose not to take that approach. I would rather use different configurations, as appropriate for the dive plan and develop proficiency in each of those configurations. It will take more total dives to be proficient in multiple configurations than to become proficient with just one all-purpose configuration, but I think the benefits will make it worth the extra time and work. You mentioned possibly feeling unsettled if you were to use other than a 7' hose. That is the kind of thing that makes me say "that is unsettling to me? That is the thing I need to work on." Things that don't feel comfortable or natural are the things I evaluate and say "is this reasonable to do? Should I be able to do this comfortably?" If the answer is yes, then my discomfort is the signal to do it until I am comfortable. Of course, the answer might be no. "No, I don't want to dive with a configuration that dictates secondary donate." In that case, I recognize my discomfort as the signal that that is not something I want to do.
I think the most important thing is to recognize my limitations each time I work with something new (well, ALL the time, really). When I start with sidemount (eventually), I have to recognize that even if I have 500 dives by then, my first dive in sidemount is still my FIRST DIVE in sidemount. When I eventually go CCR, everyone says you have to learn to dive all over again - and I would approach it that way. I think the only real problem with deciding to use different configurations is avoiding the lure of complacency that might tempt someone into confusing 500 dives in one configuration as being the same (or nearly so) as 500 dives of experience in some new configuration that they are using. In the end, each configuration becomes part of its own mindset. You can choose to develop one mindset from which to approach all diving. Or you can choose to develop distinct, but similar, overlapping mindsets from which to approach different types of diving. I choose the latter.
It may take me longer to get "there", but I think I'll be better for it, in the end.
