I use a "fencing" position, that you could also call half-surf-stance.
I allows max paddling power on both sides of the board, since you have the shoulders facing forwards, and good balance since your front foot is aligned with the stringer: moving your weight between the heel and toes will not offset your balance.
My weight is on the front foot, the rear leg is acting as a "bike stand" to counter the push of the wave: the hollower the waves, the farther back the rear foot.
People on tiny narrow boards may prefer going into a full surf stance, so that the feet are on the stringer, and it is easier then to balance a very narrow board, especially with narrow noses, at the expense of paddling power.
There are some take offs captured on my videos here: