eshcI probably should have mentioned they will be only used for resort skiing in Australia so powder is not exactly a huge consideration.
That is also why I didn't mind going for something shorter than normal because I travel with my other skis and always have them for backup here.
Since you are skiing in Australia, I would get the ski that skis slightly better in powder.
The fresh snow we get is really heavy and wet, so if you have a ski thin underfoot, you'll really struggle.
I skied on the chronics during a 'pow' day and they were pretty good whilst one of my friends was using the Afterbangs (thinner underfoot) and he struggled quite a bit.
I would say don't get a ski under 90mm underfoot for Australia, and skiing a wider ski for park is pretty popular.