Might come off a bit unfriendly, (not intended so), but here is my take on this.
I'd say that 99% of the "problem" is the rider. Ever since the IQ all Polaris powder sleds have been progressively better and better, easier and easier to sidehill.
That said, getting it on one ski, while stationary and on packed/hard snow or shop floor will always show some traits that I never notice in motion in the soft snow. The trick when riding, regardless of sled, is not to "manhandle" the sled to fall over but to make it more or less fall over itself by minor body weight movements and steering/throttle input. Even on ice/plowed road getting it on one ski is more or less effortless while in motion if done right.
Getting bogged down in minor front suspension tuning for powder riding is kind of looking for a short cut that isn't there. For just soft snow carving/sidehilling most modern, narrow front, powder sleds would be "perfectly" rideable with solid steel rods instead of front shocks. Come trails/bumps or harder/packed snow that's another matter entirely. Yes, you can get the sled better tuned right, but you can't bypass rider technique just by suspension tuning.
My Öhlins shocks aren't there for improved powder behavior, they are there for the occasional jump and coping with rough transport trails.