I a big fan of aggressive tyres, I make the assumption that you spent all this money on a 4by so that you could go offroad, if you wanted street tyres you should have bought an excel or commodore...
wheel spin that digs you in, not the aggressiveness of the tyres. If your wheels are spinning, you have too much pressure, o
anyway, there is a great myth about MTs digging you in in sand. I would suggest that it is r too much right boot (or both).
I have found that in very fine, mineral sand, MTs act as paddle wheels and keep dragging you forward, assuming that you are moving at all.
Obviously in rock having a conformng tread face is super important, and the greater void between the tread blocks of a MT also helps here.
Success in 4wding is about just two things, traction and clearance, you have less than 1/4 of a square meter (or thereabouts) of contact with the ground, make the most of it.
remember that "one revolution of wheels + no forward movement = bogged" more wheelspin is not going to make you suddenly start moving again.
cheers