Seems like the one thing y'all 99% lack is a spirit of adventure. Perhaps Rich is right and you've just been institutionalized and brainwashed by the biases and idiosyncratic predilections of "instructors," "formal training" "mentorship" and "experience." Whereas you see three tank neck o-rings and robotically think "three potential failure points," I implore you to reach for just a little bit of vision, and seek the less-pessimistic flipside, which is three potentials for non-failure, and thus three potentials for a really great cave dive, which is a whole two more than you'd have if using a single AL80. I think this is what the OP is seeking, and I for one welcome the opportunity to learn more about what he is planning.