On Auntie, the coarse control line does not have a dead end. Instead it terminates in a line that connects into a pulley system in the tiller (via the plastic bobble and loop shown).
The twisty grip on the in the tiller has leverage from twisty grip being bigger than spindrel system and also a couple of blocks, resulting in an "umpty to one" force magnification by the time it leaves the tiller (and connects to the bobble) .
This way the flappy gantry can be moved by the coase control (on the cleat at "dumpty to one") and by the fine by twisting the tillers and moving the dead end of the coarse line (at umpty to one x dumpty to one ).
Connecting via the bobble means that if the twisty system fails it reverts to coarse only. I am sure someone else can supply the umpty and dumpty values , I think these are both of the order of 16.
Hope this helps.
EJ will have the same coarse fine system, except I have not yet managed to fit the fine bit. Last weekend it became obvious that now I am on the wire a lot more I am not able to work the cleat systme as I did in BS, so implimentation will be imminent.
