HI Erik, sure, 156 will be better than the Viper for all of the above- but if you are 90kg and riding in 12-18knots, gybing and tacking/footstraps, then a narrower Gecko should also be fine, no need to go so big - I think the Eagle 148 or Gecko 135/148 should all be more than big enough. Feel free to go to Duotone windsurfing to get the latest info on the options there too, on the Disqus channel.