Here's how you check:
There's a center boot line on your boots somewhere. You pop dem boots in, and then flip one ski around, and line up its tip with the tail of the other ski, and its tail with the tip of the other ski. Then you measure the distance, and divide it by 2! This will tell you how far back from true centre they are recommended.
Seems like a pretty natural mounting point to me, you should be fine. Those skis will be epic for pow. My bacons are -6 and I love them there. Needs a lot more forward pressure (compared to park skis or my S5s mounted -3), but its a good thing once you get used to it.