Eric, that rigging guide on the Gaastra site is just terrible! I'm so sorry! According to it, they recommend just one outhaul and downhaul setting for each sail. Check out the rigging guide on the sailworks site as a comparison of what a good rigging guide should look like. I'm not saying to follow those sailworks instructions. But after reading them, I would contact Gaastra to find out why they don't give similar guidance on tuning. Maybe they really do recommend only one setting. Hopefully not.
Viking, where do you get your information, since it doesn't seem to be published by Gaastra anywhere?