General tips

[Roger 485]

I have recently stared sailing my Supernova, my first time in a single hander, only in light winds so far. Can anyone help me with a couple of queries.
1) My sail has screw tensioners on the battens. any advice as to how much tension I should put on the battens
2) I find that if I sit forward (by the mainsheet jammers) the boat generates quite a bit of weather helm. If I move aft and lift the bows (brings the centre of resistance further aft) the weather helm diminishes. Is this normal? I weigh about 94 kilos (15 stone). I have always understood that it is important to keep the transom out of the water to reduce drag, and to maintain the longest possible waterline length - these are not the case if I sit aft.