When Im fletching blazers with mine, I set it to as much offset as I can get and still have both ends of the vane contacting the shaft, Im not sure of the degrees. I shoot a fall away rest so I can shoot lots of offset with the blazers. I also use the straight clamp, it doesnt seem to matter with the blazers, theyre too short to notice any helical from the clamp. I set the rear of my blazers at the first large mark on the clamp, 1 inch from the rear of the clamp. Hope this helps some.