Another question: When you say "curved track", do you mean a track bent to the radius of the foot of the jib or do you mean a radius greater than that but less than the radius of a straight track?
Curved track is just that, any track that it not straight.
Nor do I think that there significant difference between a curved track and a curved track that is exactly at the radius of the foot of the sail. Actually there is a smooth transition in behaviour from a Curved track at foot radius to a curved track to a straight track. The straighter the track the more it will behave like your system. The more curved it is and the more it will behave like the curved track at radius = foot jib. I get the impression that you think that there is a jump somewhere.
With a fixed jib sheet, when the car moves in, the jib clew moves up slightly and the leech tension is eased and therefore it opens slightly. The slot does not become closed off.
Don't agree here. Why would the car move in (when using the setup I described) when the sheet is left as is ? It will not do that as a result of any chance in wind force. It can actually move in ONLY when the curve in the jib sail alters for some reason (backwinding it ?) but your system does that as well and at extreme angles even the F18/Tornado systems will do that. In the very extreme case this is called "SELFTACKING". Anyway, point is the initial assumption of your statement is wrong as it doesn't happen withoiut the crew actually forcing that movement and therefor the following conclusions are meaningless. In all other aspects the system is quite similar to your setup.
Wouter
