Replying to Thoughts on shorter skis?

I am 5' 10", 150 pounds, and I ride short skis. I was a little tight on cash for the past couple years, so I have been riding 161cm very old full camber Chronics. Last season I had enough money to pick up some new skis and I bought some 179cm Blizzard Peacemakers, which have tons of rocker. Now I'm in the market for some new park skis, and was looking at Surface Blanks. Since I'm so used to shorter skis, I was thinking I should get the 170s and not the 180s. Thoughts?