mount on the suggested line

The 189s are not hard to play around on...they are super jibby and playful. Yes, I've had them in wide open spaces and would never personally want the 179 when going fast in open areas. This type of ski is meant to be mounted pretty centered, so you have less tip than a more traditional stick.

For reference, I'm 6'3" 190#. I have the 189s and never considered the 179, but I'm also a bit bigger than you. Keep in mind that the 189 measures out to more like a 195. The 189s, though bigger, are still plenty playful and jibby. However, the 179s will be that much more agile if you plan on skiing them in the park.

Where are you going to be skiing?

I mounted mine on the suggested line, which I think is +5 or +6 and it felt spot on.