Replying to Chronic Blend Mounting and P12 vs Px12

I recentally bought a brand new pair of chronic blend 179's. I ride 80% park 20% back and I live in colorado. I have a pair of ar5s and some dynastar candides but the chronics will be my new primary ski. I was just wondering were people were mounting these. I was thinking about 2cm back but is that back from the lines on the ski or true center.

Also I need to put some bindings on there. I have allways ridden looks with the heal turn table. I am a big guy (6' 190) and they hold up well. But I am kind of hesitant of the new looks. Has anyone had problems with them breaking or any other problems advantages over the old p12's.

Synopsis:
1) Where to mount chronics
2) P12 vs Px12

I looked at every thread I could in the search bar but didn't find what I was looking for thanks.