use the same hoses on all dives. The necklaced secondary is very superior to the dragging octo, because the retainers never seem to work. I spent last weekend in Cozumel watching new divers dragging their octos on the reef. Yuck!
The hose doesn't have to be retained behind a canister light. You can hook it on something else or rig something up, like, say, a knife sheath on the right to hook it on. As I've said before, I hook mine on the bottom of the handle of my right side Halcyon weight pocket when not using a canister light.
I have a sliding bolt snap on my primary hose near the regulator, rigged with an O ring so I could pull it loose if it got trapped. When not using the long hose, you may clip it to your right chest D ring to keep it out of the way.
On the Cozumel trip, my secondary started a minor free flow. I clipped off my long hose, picked up the secondary, and breathed from it. The free flow stopped for a few seconds with each breath. I completed the entire dive that way, without incident. I found out later that the secondary had a plastic plug blown, which I'll get fixed, but my point is that the long hose and necklace setup made the incident very easy to deal with.
I think it is better to stick with the long hose on all your diving. It is only a matter of time til you get a backplate anyway, I'll bet. You'll never go back.
Anybody wanna buy a Transpac II, size XL?