Your draw length can still vary with a double anchor, I have always used a double anchor. Slight changes in open stance can produce varied draw lengths, the bow shoulder jamming up or goose necking can change the draw length more than most realize. It was said that Hill drew to the back of the head. Quite often in the videos, one can see him draw a bit short, not reaching his finger to the broadhead draw length, perhaps that is why short recurves did not work as well for him. I would think that one is really jerking on the draw if one could jerk the arrow off the string on broadhead contact. I shoot pretty fast and it is not a problem for me. But like I said before it easier with woods, they are easier to get the length exactly right.