Our last trail build was 1 "hard" flow trail, 1 intermediate to easy flow trail, 1 half and half flow and tech and 1 full root gnar trail. My fav is the root gnar trail, just because of the challenge and steepness. Sometimes you get amazing "flow" out of tech, which is at a certain speed and aggressiveness the trail "rolls" better than if you are not attacking it. That is my kind of "flow". One thing that is annoying as F on true "flow" trails is grades that require you to pedal your ass off to get to the right speed for a jump, some of which that just doesn't work as designed.