There is no handicap in any type of snow tested heads up versus a bone stock 5.1 irregardless of depth or water content. You do get exponentially higher performance with higher water content or more packed the snow conditions.
The reason for this on this particular vehicle is because the drag from resistance of windage and evacuation space cannot be overcome by the 800's limited HP. IE A balance of pattern, throw, evacuation and windage in use with the amount of power/force available is what propels the vehicle. On this vehicle you get better performance with less drag resistance. To compete in net performance you have to add significant HP to overcome the resistance.
Camoplast (the contracted manufacturer for Polaris) knows this and it's been clearly proven over and over on this application. The problem is the consumer is ignorant and marketing demand drives design. Guys would stuff 3" paddles plus in there if they would rotate at all! Add more HP and more evacuation space to lessen resistance and you'd would have a performance increase but as things stand right now on this application 2.1" is the perfect setup and that is why I coach people to do this. It gives you free performance over your buddies' stock application all day every day.