Might be something to consider trying out on what you want to use as an all mountain ski. 90% or more of the time I'm riding on a Jeffrey, I'm going forwards, and -4 isnt so far back to put the ski off balance that wildly to effect spinning.
Let me put it another way, when I'm skiing switch, -4 mount feels pretty similar to a dead center mount, I dont notice that much of a difference. When I'm charging a line or skiing through trees and pow, I want -4, not dead center. I go for recommended just because its best for my skiing style and where I want my ski to perform best. Obviously, for a cat like Vincent Charette who skis his Jeffreys on pretty much anything, its a different story. Use the advice here to sort of gauge where you are on the scale and what you'll be doing on this ski most / what you want it to do well, mount accordingly.