Mine (front only) are on the softest setting and work just fine.
Richard, when I took Rosie to New Elms to get her checked over, my rear Avo's were set at softest setting, Darren told me off saying they will have no damping what so ever and recommended 2-4 on the rear and 3-5 up front. Rosi is now set up with 3 click rears and 5 up front, not to stiff and works well.