It should not matter what side you mount the
actuator on. You are almost dead center of the arc you want so moving to the east side changes nothing. The key is actuator stroke and positioning in the mount. You are wanting to move 49 degrees east which should be no problem and 44 to the west which again should be no problem. I have a 24" actuator on a 8.5' dish. I would guess you would want a 24" as well to get the stroke you would need. Do not think a 18" unit will do the trick but I could be wrong. Maybe some folks with 18" units can chime in and tell you how much travel they are getting.