I'm not a big fundi on towing, but the little i've done involved diving boats and hobies. We have pretty soft sand on our beaches here, but with 4 wheel drive (not always needed), 0.8 bar pressure, mommentum and driving just of the high tide mark makes it pretty easy. When our guys get stuck, a little backwards for a run up, or a big loop to build up mommentum gets through most sand.
just a thought
Clint