Dan,

I also have heard that spinal compression is a factor when shoulder harness
points are not above the shoulders.  I have also heard some pilots complain
that the harnesses add some weight to their shoulders as they are presently
configured on the 320-360 planes.  This becomes a comfort issue.

I opted to mount the hardpoint on the top of the fuselage behind the
fuselage roll over bar together with an air box containing two fans, the
headset connections, headset storage brackets and cabin lights.  No weight
on the shoulders, out of the way for baggage and presents a neat compact
modular unit approach. There is a weight  penalty, (about 4-5 lbs including
fans, NACA duct, air plenum box at tail and air tube) for these gadgets so
if you are "racer" and weight is important, don't do it. If however, you are
building a cross country traveler and comfort is important on that hot 100
degree day on the Boise, ID tarmac; then it is a nice accessory.

Bob Smiley
N94RJ