Well, I tried both methods. They are best used I guess at the end of the tiller, otherwise you spend more time in front of the computer then in the garage..
It's pretty tricky to get the bow vertical.. And you need a patient photographer.. If you managed to do it, it's pretty simple to apply the ellipse. On the other hand you can draw the ellipse in many different ways and maybe get confused doing it.. It probably just takes some time getting in right.
Danos style is much easier to accomplish and I prefer having the pictured flipped with the bow down and string up (opposite of tiller tree).
Thanks for tips!