rhuntley
Contributor
I have not been in this situation YET (it's coming up fast though) but I did read on another thread that what some people do is bring three tanks. On the first dive they breath one down more than the other, then swap the low tank for a full one the second dive.
Wouldn't breathing one tank down more than the other be the opposite of what you want to do? If something happens to the tank [or reg of the tank] with more air, your dive would be limited to the tank with less gas, or feather breathing if possible.