I'm afraid I have to disagree with the snag issue. On my reg, (MK15) the hose routing is actually a little better turned around like that; basically all I had to do was switch the HP hose to the other port. I looked at pretty carefully and had someone about my size put on my rig so I could see what it looked like. BTW, I'm talking about yoke; for DIN I have no idea how it would work out. But, with the yoke knob pointing in, it removes a potential snag, as the knob looked to me to be the most likely snag point. The hoses actually seem to protect the barrel from being a snag point, as they are near the end of the barrel and sort of span the "gap" between the reg barrel and the top of the tank valve, discouraging something like a monfilament line from getting caught in there. They don't route back away from the tank; still basically out to the sides. The LP hoses route in the same direction; I have a swivel, so this was unaffected.
The tank valve on the other side and the confusion it might bring to a DM or buddy is a legitimate concern. For me though, other than making sure the valve is on before diving, I'm not sure what real-life problem this would create. I suppose if you (or some else) had to shut off the valve in mid dive there could be confusion, but I have a hard time imagining why you would do that unless you had catastrophic reg or valve failure, in which case your primary concern would be getting air from someone else and getting to the surface safely. Forgive me if I'm missing something, but I'm not sure what added danger would arise from not being able to shut off the tank valve quite as quickly in that scenario.
Reg recovery with my set up is essentially unchanged; if anything it's a little easier to reach the point where the primary and secondary meet the first stage. I practiced it, and that's what I found.
Exposing the 1st stage to hazard is, I guess, another legitimate concern, but really, when I looked at it, it did not seem significantly more exposed. It's still not as far back as the outside of the cylinder. And I'm using the set up in open water; maybe in a really close environment this wouldn't be a good idea. But, the whole set up is still more streamlined than it would be if the tank was sitting a couple of inches off my back.
Anyhow, I'm not at all offended by the multiple posts not liking my idea, and I'm interested in other potential problems; it's very possible I've overlooked something. Because my plate holds the tank so close in, and my reg is pretty big, and I'm a fairly small person (5'8" 160lbs) my head was really hitting;I couldn't look up at all. It was either go back to my MK2, ditch the jetharness, or be really frustrated.
BTW, I tried Tobin's idea of "offsetting" the reg barrel to one side a few degrees, but that really messed with my HP hose routing.
