Replying to Another Mounting thread....

Well here it is again, and yes i did use searchbar and nothing turned up.
I have 07 Armada Ar6s in 166 w/ Rossi Axial 120 Pros and im not quite sure where to mount.  For most of the season I'll be in the midwest slaying the park, but for a few lucky days, i'll be in Colorado for some pow and bc.  I want them mounted where i'll still have enough tail for decent switch skiing. 

I was thinking maybe -2 from true center but I dont know if i'll still have enough tail.
Any suggestions?