A whole hour and a half! What took you so long Dom?
OK, I understand the thinking and you're probably right - it's just that it doesn't seem too much of a hindrance to me to take my octopus from the left where it's clipped to my BCD and stick it in my mouth. That could of course change at 30m - especially as i've never had it happen to me before - so hard to say. I take on board what you're saying though.
So with a DS4, the best way of routing my AAS would be to the right and then under my chin... What about the length of hose? My AAS hose is pretty long, couldn't that be an issue...?