I was told that, in drivers, the loft basically decides how square the clubface is on impact and the shaft stiffness determines height.
As such higher handicappers usually should use higher lofted drivers to assist in squaring up the face on impact as normally they will leave the face open on a driver and squirt it right.
The shaft should be decided by swing speed.
I, like murph, was fitted for my 9.5* tour head. But when I'm not hitting it well it usually leaks right.