Mine have Pivot 14s - used 2nd hand came with them. After skiing them a lot, appropriate, even though I don't really care about Pivots one way or the other.
I believe mine were set up when the Pivot 15 was not available. So Pivot 15, I second, for both the on piste and off. (Unless you want to push them more towards on piste use, or experiment with mount points. With the Pivots, they are great on piste already, though not as specialized.)
Those wide shovels are there for a reason, I gather: they are in big ways not like the AX, except in excellence.
With these bindings, In terms of carve on piste, they turn more like a more round-turn shape AR than a 175 or shorter AX, with a bit more pronounced turn, but with more forgiveness also. A strongly sideshape/sidecut-effected carve, you see. In the fall line body separation/upper body still turns, that ski is a "cheater" for.
But in terms of a soft snow day (up to maybe 3-4" for me personally), and a soft snow day in crud and bumps, the reason for the wide shovel becomes apparent, and versatile, in a way the AX doesn't work. The whiteouts do not stall, catch, hook, dive, etc. in soft snow bumps and crud, that I can tell. And they float some. A very pleasant surprise when I found this out. I'd just switched to them from my AX, because with some wind drifts, the AX was getting overpowered in the depth inconsistencies. Not the Whiteout.
(Don't get me wrong, I love both skis: just different, and different strengths.)
