I took my octo off 17 years ago since most of my diving was solo or with friends and went separate directions . I just wonder what you think of this and your type of set up . I have a scuba pro second that goes on the BC power inflater but have not used it either . I was thinking to lengthen the BC inflater hose and dump valve to use as a workable second stage .
I think how we configure our equipment for solo diving depends a lot on the type of solo diving we are doing, the possible risks involved, and where we are diving.
I do as much solo diving in places where there are no other divers around as I do in places where there are lots of divers. Experienced has taught mke that I have made the most rescues of other divers while freediving and while solo freediving because I've had a bird's eye view of the dive site and I have been at the surface when victims have bolted then needed help. I don't change my equipment at all when solo freediving. I use mask, fins, snorkel, weightbelt, wetsuit and long blade fins without "safety" vests or other things that you can't activate when unconscious. Three SWBO's (fortunately I survived a solo one as well) have taught me that when you black out, you have no idea you are going to black out. But, when you feel like you are going to black out and die, you are probably aren't and that's just the CO2 screaming at you! Which probably means you didn't drop it low enough to con you into thinking you are feeling great when you are about to black out or die.
Based upon the experience of minding my own business and becoming a rescuer, I want the ability to rescue others if I encounter a low or OOG diver while I am solo diving. For that reason, even if I didn't need a back-up regulator myself, I want it to help others. A back-up regulator also allows you to more safely inflate open cell lift bags or DSMB's. Working with bags is more dangerous for a solo diver so having a ready cutting tool and a way of inflating the bag to keep it away from the body and equipment is a good thing. You can go to your back-up regulator, use your primary to inflate a bag keeping the bag away from you, then return to your primary after the bag is deployed.
For most of my solo diving, I wear my Hogarthian doubles rig. Even with the shortened corrugated inflator hose, it can still reach my mouth and I demonstrate using this in class as a third regulator when I teach tech or solo diving. I have yet to get a lung infection from doing so. I wear my Hogarthian rig simply because it works fine for a backmount solo diving configuration and I don't need to change anything from one dive to the next. I can do a solo dive then go right into a team dive with all needed gear.
For recreational level diving, I have the redundancy I need with the isolation manifold. If I add a Nitrox 50 bottle for a cleaner ascent, I have the added benefit of a safe redundant gas source apart from my doubles from 70 feet to the surface. A bottom stage will give me either 80 cubic feet of redundant gas from the bottom up or 154 cubic feet if I dive the bottom stage and save the gas in my doubles.
I have done a lot of solo cave diving in backmount with a buddy/stage bottle, but I recently have acquired a Nomad sidemount system I'm going to employ for solo cave and other solo diving when it is needed.
One day, when working as a lifeguard, I was performing some underwater maintenance and installing moorings for a sailing regatta. I found that I could use some scuba rather than breath hold dive to make my job easier. My tanks were empty, but I had a 19 cuft argon bottle filled entirely with air. I added the bottle and a stage reg to my weightbelt by taking the loop from my canister light and then wearing the bottle on my hip. Worked great!
Ultimately, the nice thing about solo diving is that we can think and problem-solve for ourselves. Solo divers are often rugged individualists who are confident about their abilities and accept the risks of choices they make. When it comes to equipment, we often must balance what we don't need, what we do need, with what would be nice to have without having too much or too little. Too much gear can be as problematic as too little.
There is a difference between a solo diver and someone diving solo. That difference is often knowledge. With that in mind, I cannot comment whether I think getting rid of your octo is a good idea or not. You are the one who knows where you dive, how you dive, and whether or not a back-up regulator on your primary gas source is useful. I would bet that it would be useful even if you never use it. When skydiving, I never used my reserve canopy, but I'm glad it was there. It sounds like an octo incorporated into your BC LP hose would be a wise decision. It's minimal and gives yu the option. Plus, from teaching using the BC inflator as a third reg, I really wouldn't want that action to be my next choice after a primary failure.
In order:
1) Primary failure switch to back up regulator
2) Back-up failure switch to buddy bottle
3) Buddy bottle reg failure switch to inflator hose breathing (if primary first stage works)
4) If all regs have failed switch to tank valve breathing buddy bottle
Having a bad day like that would mean that someone probably no longer wants you alive and you'll probably get killed driving home.
I'd rather not have to do a primary reg failure switch to inflator hose breathing.
