Replying to Rossignol slat vs S5?

I am looking for a mid fat ski to mount 1 back from center and use for like 50-50 park/all mountain. I just ordered slats (they're like $250) and have been hand flexing them and considering returning them. They seem a little bit softer than I would like and they're also a bit heavy. I am considering maybe getting the older, non-rockered S5s (even though they're somehow $100 more expensive anywhere I can find). Has anyone ridden both and can compare? I'm 6'3'' 180 lbs, ski east coast. Other skis I really like are volkl walls.

Thanks!