Well, as to the mounting position, my instructor was concerned about the valve and or gauge being damaged by impact either on the boat or on an obstruction and had me remount it for my class. I had originally thought that with it inverted I could then reach the valve in the event of a freeflow, but my instructor's reasoning was that the risk of damaging the vlave or gauge outweighed the risk of freeflow. I believe that his reasoning is based on cave experience. In my case, being unable to reach the valve on the pony means in the event of a catastrophic freeflow means my dive would be over at that point. I hadn't thought of a low level freeflow that can't be heard. I still dive with a buddy but as we all know, the buddy system isn't infallible. As to the main reg, I don't turn that up at all. As part of my prep, I turn up my pony reg to help prevent a free flow hitting the water then back it back off once i'm situated. Of course, we both do a leak check as soon as we're in the water, but that doesn't preclude something happening later on. If solo diving, a gentleman suggested a wrist mounted mirror to look behind to see the valves. I really liked that idea and believe I will adopt it. I thought of slinging the bottle, but as my buddy has been having constant issues trying to get it to lay to his liking. So for now I will continue to use back mount. But I may still try to go inverted again. I realize as I continue my path to Tech I'll have to solve the sling problem sooner rather than later.