You're correct Perry...Alice's 106 lbs on her 75mm waist would float as well as my 156 lbs do on the 90mm waist. We've actually experienced this in knee high snow a few years ago at Aspen.
When we're talking about fat skis, my recent experience really help clarify what I really wanted in a fat ski. Some posts back when I owned the Watea 84, I really liked the skis performance in crud, groomers, bumps and some shin high snow. I did feel the ski was lacking a little zip and a little float for the deep stuff....and maybe just a bit too damp for the way I like to ski. My experience with the 94 showed me a different ski. Not sure whether it was the length 178 or the dims, but I had a heck of a time keeping the edges at high edge angles in snow below the ankle. Obviously, I don't need those kinds of angles in deeper snow but I wanted more from the ski.
Finding that ski no matter what make or model...a ski that allows you to change little of your skiing skills ski to ski I think is key. If someone would have asked me whether I thought I'd be skiing a twin tip, my first reaction would have been, no, there's so many other choices out there. I am fortunate to be able to enjoy that 2nd ski and to get a good number of days on the snow. Having that second ski pumps up the fun factor when conditions significantly vary.
As far as Alice's next choice, I'd even like her to try a twin tip next time the conditions merit a demo. Hey, yea never know..
Keep us posted on your Ski evolution and good luck!
Best,
Gary