I have a few poorly lite pictures of my snuffer however I am using the Guck "Skunk" Mid Pole Snuffer on a home made spinnaker pole so I don't know how these will relate to what you have.
Snuffer Location: The center of the hoop is located approximately 22 inch in front of the apex of the forestay and bridle. You can position it closer to the apex but the spinnaker tends to hang up on the bridle when snuffing. Positioning it further out increases the windage. There is no correct position that I am aware of.
Anti-rotation Restaints: There are 2 methods I am aware of for preventing the rotation of the snuffer hoop and pole. One is to pin the pole at the base and the other is to use lines attahced to the hoop to prevent rotation. If you use the first method, the pole you use must be structurally sound. I'm using the second method because my pole is only 1.5" OD aluminum (Sunfish Spar) and I don't think it would handle the torque loading of pinning it at the base. I use a total of 6 lines to restain the pole. 2 line attach the tip of the pole to the bows. 1 line connects the pole to the apex of the bridle and forestay. 2 lines provide side support of the pole at the snuffer and 1 line prevents rotation of the snuffer. (See picture although it dark and hard to see)
