Replying to S5 to add to the quiver?

I currently own Moment jibs and Rockers..But I am likely to be skiing a bunch of pillows and BC freestyle in switzerland (Saas Fee and the surrounding BC).. I am 5'8/9 and 140 Pounds.. I want to add an all mountain ski to the quiver and was originally looking at Bacons but I can get a really good deal on Rossi S5s with SAS 140s and so i think they will be perfect.. Bit narrower but that will be quick edge to edge and also lightweight.. What dyu think NS? I will be on the 178 and also wondering about mounting point.. I can't work out where the Lines are and which of the 3 is recommended.. I am thinking about going for -3 regardless of the Lines?