I have a 310, but the idea is the same. Your spinnaker pole should be the length of your J measurement (on a 310 it is 11'9"). As the 310 has what appears to be an electrical track running exactly right up the front (as evidenced by the rivets) I had to use a ring which straddled the track. I put it at eye level (I am 5'9") and that has worked out fine. For a track I would guess you would want it to start a little lower and go up a little higher.The main idea is to be able to level the pole out with the topping life and the track for best sail trim. Does that help?