I got my original setup information from the Slingshot Foil Academy. The suggestion is that the sweet spot is 43" (109cm) from the front Tuttle screw to the centre of the mast foot. Now I see in the Balz Muller video he is suggesting that 85cm is the place to be! This is a huge difference. Just wondering what distance are you finding to be the sweet spot and with what size sail. I am currently at 104cm with a 6.5m sail and about 101cm with 5.5m using the Slingshot Ghost Whisperer 101 foil