71 yr young powder skier, right on!
You can probably stick around 170cm, if the sizes are in between, a little shorter, but not longer, IMO.
I'd look for something easy on the knees (over dampness which ususally means metal sandwich, and therefore, heavy). That would be wood or foam core with fiberglass, no metal needed. Try 114 waist or more, all the way up to 130ish, if the snow is deep. All new shapes would be an advantage as the fascilitate easy turning and great float. That said, many companies have something like that to offer. Just some ideas:
Volkl Chopstick, Volkl Kuro and if it's not very deep, Volkl Gotama, 2010, and Fisher Watea 114 (traditional camber though), Rossignol S-7, Salomon Czar, Salomon Shogun, Praxis Powder, 4- Front something, Armada J.J,. having a brain lapse, but others here know the easy turning new shapes out there.
Tell us how you like what you try.