Tobin,
I have discovered that the nicest way to dump the OPV (at least your OPV with thick cord) is to hold the string in the closed fist with the last three fingers, while the thumb and the index finger hold the valve itself in position (to counter the pull). This way the wing is not pulled and the bubble stays near the valve.
Eelnoraa,
As for the position, the wing usually wraps around the tank, and the valve ends being on the "outside" of the tank - facing left on the left side of the diver, in a pretty high point, where the air is. If the valve would be installed on what you call outside, it would be in fact caught between the wing and the tank, in a position very hard to find/use.
I usually find it harder to dump using the inflator, because this forces me in a vertical position in the water. If you cannot dump from the OPV you are maybe staying in a head-up position. There's no pull-dump corrugated hose because it is easy to dump from the OPV when horizontal, and because if you pull the corrugated hose, you would basically pull the whole upper part of the wing towards your head, shifting the air bubble to the lower side of the wing, and failing to dump air because of that (the corrugated hose elbow would not be the highest point anymore).