One of the challenges of the laid back riding position is how you change gear, many use cables but my experience is if they are slightly out of adjustment you end up not able to change gear. Rods are positive in their action but the routing is difficult,so i am going for air cylinders, probably fed from a sodastream bottle of gas, as easy to get in local supermarkets, and operating 2 cylinders, one for upshifts and one for down, as you need to get off the course after the run so need to change down again after the run.
Here is a quick rig i made up that seems to work quite well and is reasonably compact.