Paul,
I'm afraid I've b een a bit slack with posting my mods onto this forum. I've had this mod for a couple of years and perfected it about 1.5 years ago.
Essentially it's a design I stole of the skiff I had, and uses a length of curved track with a roller car. This is all bolted on just forward of the Mast Step and the control lines go fwd before coming back to the cockpit. It also requires that a new headsail is made up to fit the dimensions.
I'll try and get a few pictures of the process when I fit John's on the long weekend.
The main deal here is that this system does not need any work to do a tack at all and works in all wind conditions. The sheeting system ends up being a 3:1 advantage and you never need to use your whinch handle again. In fact my whinch handle had seized up from lack of use.
I also invented a very easy roller main too!
Brian