I’ve got a 40 cu ft pony bottle for use as a redundant air supply (wearing it left side mount) and would like to route the hose from the left and around my neck when used.
In my left side mount position, what are the typical hose lengths used for 40 cu ft pony bottle kit? 32” or 40”?
If the diver uses a 70 degree angled 2nd stage hose adapter, what affect does that have on the deired hose lengths used.
My own setup when diving sidemount with a pony is AL 80 left, AL 19 right. The right-side is redundant-only; and I don't breathe it except as practice or to verify it's working.
On my pony-side, my regulators have a 7ft hose, mostly tucked under bungies. Because the hose is tucked under bungies, there's almost no down-side to the long-hose. It's effectively a flexible hose-length, or about 32 inches when tucked., but pulling on the hose easily converts it from something like 40-inches to 7ft of usable length. The hose has never come unexpectedly untucked from bungies.
Do you need 7ft? No, not really. The original idea though was if I ever was in an air-share scenario
(which I mostly dive solo), the standard "rule" is that they grab the reg on the brightly-colored hose, and that's theirs. If necessary, I can even remove the cylinder entirely and hand it off. My left-side would still be attached to my inflator-hose, and have my larger air-supply.
I use the same regulators when diving normal sidemount (2x AL80, or 2x HP 100s)
The reason I suggest you consider 7ft, is because it sounds like you want to play around with hose-routing. By doing this, you effectively have a flexible hose length, and can try everything from 5-inches to 7ft. The 70 or 90-degree adapter is irrelevant to hose-length, as it's basically adjustable. I have a 90-degree adapter on mine.