I went to Spring Fever couple years ago, got to meet Wouter. I took the redeye and drove from Atlanta, so I was pretty tired. What I remember may be wrong because of this. Randy Smyth gave a talk about trim. After the talk, one question that came up was about leach telltails. His comment was ...why are you looking back there when going up wind? You will never keep the flow attached back that far, and if you try you will be sheeted out way too far. He uses telltails that are very close to the mast. The one close to the spreaders is the one he uses to adjust prebend.
Randy seems to go very fast

Ken