I've been running winters for a few years now and down to about 5mm maybe 6mm on the wintracs
In 4 inch deep fresh snow I couldn't get up a very steep hill near me where as I could the last time it was bad. Only difference is last time it was compacted snow and ice. This time I just got wheel spin no matter what the traction setting or throttle input. Either less tread made it harder or the fresh deep snow is harder to conquer uphill. No problem on the flat and got up another similar hill with driven in snow no problem.