STOP with the thoughts of preventing your ski tips from sinking into the snow. we are not talking about water skiing. In pow, crud, and all manner of unpacked your skis WILL find a depth of travel where they have enough vertical support in the snow to support your weight. Nirvana is what we call face shots in deep powder. These occur with light and dry (I prefer Utah light and dry, but any will do) up to about mid thigh (and perhaps with it very light you will sometimes sink past your waste-- heaven) and turns in the steep that cause waves of light snow to wash past your face. In this blissful situation you cannot see you skis, nor do you want to. Your tips become visible only as you huck big air off a cliff, and then too, you do not want to look at your tips -- but that is another story entirely.
Your ski tips WILL NOT sink deeper and deeper into the snow. WILL NOT. Not many years ago we regularly skiied in the back country with Karu XCD's I doubt if these were 65mm wide at their widest -- splinters really- they didn't float like a water ski, but my god we had planty of fun even though you couldn't see them-- makes me wish I was about to jumb into the the top of Gunsight right now---- today's wider skis are sometimes helpful and certainly fun, but good skiers have gotten by without them for a long time.
spends some time with lessen and some good skiers- watch others who are good
trust us, put those hands out front, pull your feet back and stop skiing to avoid falling-