I dive standard recreational dives, and am involved in teaching the same. My Octo has about a 60 inch hose, is on my right, under my arm, and tethered with a secure keeper just right of the center of my torso, from which it can be pulled away with no "untying."
At least once a year I practice with one of my dive friends swimming with myself and him both breathing on my tank, and then both on his, each using the others octo and each using the other' primary. We do five to ten minutes each way. I have an alternate air source reg that comes pretty much staring off the hose, as opposed to from the side, and that configuration works fine. The hose is short enough it does not dangle or tangle, but long enough to be useable. No doubt you technical divers and cavers require a different arrangement, but for recreational diving, I like what I have. The practice is worthwhile, and I encourage others to do so.
DivemasterDennis