though, to be fully honest, more foot movement, less upper body movement. when i was riding that kind of board a lot, i found myself trimming & barrel riding from a more forward position on the board & then taking a step or so back to the tail to do any kind of hard turn, like a full cutback. it's actually a trait i've held onto & i think i makes my surfing smoother. in fact, when i feel like my surfing is starting to get spastic or flappy, i'll hop back on one for a session or 2.
i don't think it's a coincidence that the guys we think of as having a timeless style-tom curren, lopez, etc...all grew up initially riding single fins of the type you're talking about.