Hi Mezza:
my top speed with iS111/42/SSR7,6=32,5kn. I am 92kg and 184cm. Because of the wide tail(49,2cm) the iS111 works never with the small 36cm fin. It needs lift from the fin to plane free and adjustments to ride it mainly with the back feet. Pull down your sail for more loose leech, rise the boom until you have main press on the back feet and position the power joint in the middle of the box. Have fun!!
Peter