Update:
So I got
The Oxygen Advantage about two weeks ago and focused on the BOLT score and Breathe Lite/Breathe Right as
@aciampa and
@Steve Freides have suggested. My initial BOLT score was around 16, but bear in mind that was my first try at it and was getting used to the signals my system would send me when I needed to take another breath and stop the clock. I think it was pretty accurate, though. I've been doing the nasal breathing 24/7 and immediately started putting tape over my mouth at night. No issues whatsoever with sleeping with the tape and have been getting great nights sleep with it. It hasn't been a distraction at all. In fact, my wife is now doing it comfortably, and she's a notoriously finicky sleeper. The Breathe Lite/Breathe Right has taken some getting used to, but with practice I think I'm getting better at it. I do it during my 40 minute drive to work every morning, which is almost all expressway with little traffic to distract me. I do it a few times during the day at work, and I'll do it in the evening at home. I do it for several minutes each time. I'm not 100% convinced that my breathing is consistent during those practices, but the intent to reduce it is there and I pay attention to the "oxygen hunger" and keep it at a reasonable level.
I'm becoming fully aware that this is a process and, like SF kettlebell practice, perfecting my technique should be the day-to-day focus and positive results will follow naturally. On a basic level, I understand this is about increasing our carbon dioxide tolerance from our own metabolic processes. And that this tolerance, like physical strength, can be improved slowly through progressive resistance, though in this case the "resistance" is modifying our breathing .
So now for the results, and this is only subjective because I haven't retested my BOLT just yet, but my KB swings have been noticeably better in terms of recovery between sets. I'd been doing the S&S diaphragmatic breathing as best I could before, but there always seemed to be a lot of mouth breathing after a few sets as I started to wear down. Last night's practice was fantastic. I added reps to each set, nasal breathing the entire time, even during recovery between sets, which was much shorter. My grip ended up the limiting factor, not my wind, which is unusual. I had plenty of energy for another set but I didn't trust my grip, so I stopped. I'll check my BOLT score soon, but I have to say my KB practices are already improving so I'm assuming the BOLT is creeping up.
I'll keep you posted on progress. Thanks for the recommendation!