I have 176 AR6's in Ontario. First figure out how u will use the ski. There is some importance on the ski length, boot size and heelpiece track length. MEASURE the ski first to get true center in case the topsheet graphics are out. There have been some threads on this elsewhere.
Guideline - Park only go 1-2 cm back or maybe center, 50/50 park & all mtn 2-3 cm back. If you have a long ski u can go -4 or 5. But why ? An AR6 will sink too deep in pow or anything over a foot of snow so I don't see going back 5 cm.
The ski behaves more like a recreational carving ski as u go back and balances/ spins better around center. If u have large boots - size 10 or bigger and if your bindings have large heel track like Rossi's and u go back 4-5 cm then this situaltion can upset natural carve & ski flex of the tail if u go back too far. I learned the hard way. I had to remount. The shop was not aware of setbacks.
Be aware that -4 cm back on a 161cm ski can be significant. It isn't much on 181cm ski. Some of the bios on the Armada website give what the Pros use, eg: Jacob Webster AR6 at -1cm for a 181cm also for the Pipe Cleaner ---JP Auclair- similar ski Pipe Cleaner 2-3cm back.----from true center.
