One quick thought to make these work easier...

See the clevis that the line comes back to at the car? There are 3 positions. Move it to the cam side and the angle of the jaws will be higher and it will be easier to uncleat. Otherwise, the easiest upgrade is the Hobie 1075 jib cars. Fits the stainless track and has a swivel cleat mounted on top. Closest thing to the current system there is for an older boat.

Hobie Parts Page 34