You can do it like this, me, Luis and several others had been setting up similar to this. The new low profile FREE hookah adapters work great but picutred is the older style. The swivel is a three way LP swivel commonly available. The LP hose to the inflator does loop oddly back behind you--but---

----if you use bike tube from a 700C wheel--per DIR methods and put two or three loops of bike tube on your BC inflator hose and then when you set your rig up for diving pull the LP inflator hose through the bike tube material you will find that suddenly you have a very sleek set up.I have also found it best to install a 40 inch hose with a ball type swivel(get a quality one) on to the second stage octapus thus allowing the octapus hose to route down undr your arm and then bring it up and bungee it with a break away bungee--DIR/Hog style. This allows you to quikcly yank it free--bring it up and over the double hose mouthpiece and right into your or to quickly donate it to a buddy in need. The bungee is tied around the mouthpiece of the second stage as if you were tying a square knot but instead inserted the mouthpiece. Yeah, it can fall out and if it does--no big deal. If you do not understand what I am saying let me know and I can try to explain it better.
BTW, while exploring about north central Florida--my old stomping grounds--I came upon HP swivels

. YEAH. OK, well, these are very sturdy, I bought a single elbow swivel, a tee swivel. I had not seen these before but I think that OMS sells a similar type---I can research that if you like. The HP tee swivel works great for my LP hose and octapus in place of the LP three way. I also use the HP swivel on my Phoenix for an additional positionable LP port. They are 3/8ths so you have to use an adpter though but are available in LP versions as well.
James