I think a key to staying light is consciously weighting and unweighting to float rough sections. Select the right place in the trail to literally let your weight push into flow and gain traction. Alternatively Float up, not necessarily pop off the ground but push off and rise upward just before rough sections. The smoothest way through the roughest patches is unweighted float, of course you cant endlessly float, so it becomes a game of heavy in the smoother spots setting up your direction and pop to lightly float the tops or even completely above those real nasty bits coming int smoother spots to drive through the pedals allowing more traction for direction changes or setting up the next upward light float. I have seen this work very well for talented experienced riders regardless of suspension geometry, tire choice, etc. Hardtail guys that rip really rough trails will demonstrate this if you watch them closely.