Like wise on the brutal but fun. I'm having the same experience in finding traction. I've heard the vee rubbers aren't the best. But I don't have them on my Moose, so.

I'm betting summer on the sand will be easier because grains of sand can only compress so much whereas each snowflake is crushing and is ever breaking apart beneath us. Sand grain will eventually lock up and provide a hard surface. (insert fellow forumista to explain how wrong I am, here)

I've has a bit better luck in lower pressures, 6 I think. But I'm not sure I've dealt with the depth you have. Until I went over the bars yesterday. I anticipated a deep spot that turned out to be a small hill beneath and I sank to a stop quickly enough to send me over in slow motion. What a hoot!