However, please try any boat before you buy. I have a Tekno that I am very happy about and so is a paddling pal of mine. When he had the opportunity to buy himself a (like new, old demo model) Tekno for cheaps (500 euros) he did so, only to find out that the rocker of his boat differed lots from my boat. In fact, the boat behaved like a completely differen design (and not as good as mine).
I weigh sleightly less than you (82 kilo's) and would like to recommend you measure the rocker of any Tekno that is offered first. My boat has a 19.5 centimeter front rocker and 14.5 centimeter tail rocker (I measure the rocker as the distance between the floor and the tip, not sure if this is correct but it is the easiest way to do for an amateur
). My mate's Tekno (which he returned) had a front rocker of 17.5 centimeter and tail rocker of 12.5 centimeter.