Replying to 2010 Obsethed Mounting Points

Just picked up a pair of '10 179cm K2 Obsetheds with Marker Griffons. I am 5'10, 150 lbs and am wondering what are some mounting points people are using or recommend. I ski all mountain and park about 50/50 so I am interested to see how far forward you can go without hurting performance outside of the park. Right now the skis are mounted at + 3cm, but I have to remount anyways because of my boot size (from a 25.5 to 28/28.5), it says on K2 that Seth mounts at +3.5. The guy I bought the skis off of say to not go past +3. Also, even though people say only the graphic has changed this year, I noticed somewhere that the 2008/09 had 15/20 rocker and this years has 10/20, wouldn't that change possible mounting points?