Jim, thanks for pm about daggerboards. I solved that already. About the under tramp system, please explain in more detail. You have two wires, one each side, almost parallel to the hulls or almost perpendicular (or in between)? Did you attach the line to the tramp?
I got a better line and stretching is not a problem now. I am pretty convinced that the ideal point for the block is forward of the tracks. Next time I'll run the line from side to side but attached forward of the track, at the forward attachment of the bungie for the daggerboard. Hopefully it'll be close enough. Then I'll probably run it under the tramp and if necessary angle it a bit forward. For high wind I may have a second setting, attaching to the the track forward position and runing the line with more angle forward. Regarding adjustment, I'll keep using prussik knots, it's very simple. You can adjust during a tack very quickly, which is good enough for me (not racing).