Probably awesome, on spatulas i can go down runs sideways doing nose presses (hardpack) it's a pretty fun way to get to the pow.
I would also agree that those are too large, my face shot count has decreased significantly since buying spatulas, and as someone said above, part of the fun of skiing powder is skiing powder. I think skis are just at about the point of max width, certainly a huge jump in the last few years, but at some point you reach the ideal width.
My friend is certain that I will buy a pair of Pontoons, and i'm not saying that I won't, but i'm pretty darn happy with my spatulas. But then again I was pretty darn happy with my 78 waist K2 xp's 4 seasons ago......