get a roof box. I've found that for our types of skis, the roof holders, i.e. the racks where you just clip your skis onto the rail are a nightmare. My friends EP Pros were too wide for the clamp to go around, and no reverse cambered ski will fit in.
So yeah, go Thule, and make sure, not matter how many litres it is, that the length is long enough. In the UK, the standard shop bought ones only go up to 165cm
Every ski has a worst enemy; the other ski. And Gapers.