When i was first certified i told myself that i was going to be responsible for my own saftey. I did not assume that my BOW would even come close to preparing me for everything that could happen. And it didn't. I only had the basics - go figure. However in the worst possible case i would still have known to exhale a four letter phrase for the ride up in such an event.
Over time as my skills improved and became second nature i took it upon myself to continue adding/improving skills. I feel it is all of our responsibility to do so and am glad to see that other divers take the same approach. A good friend shared his mental approach to diving when i first started scuba. He told me to think of everything that could happen while diving, and then said to have an answer on how to handle it before going in the water. I live by this to this day.
I do use a low profile second air source that is inline on the lpi hose and love it. i know a lot of divers seem to poo-poo such devices, but we all have our own opinions. I do believe no matter what configuration i dive, my buddy should be aware of how it works. For me 1 less piece of gear sticking out to get snagged is 1 less piece of gear sticking out to get snagged. I like my rig to be as streamlined as possible. But that is what my diving commands. If i were diving elsewhere, with different objectives i could see my gear being configured different.