HOLY YIT. Clutch adjustment headache x's 1000
This is what I would do. Take the cable off. Let the actuator arm set itself back to where its all the way out. Drawl line with a sharpie off the actuator arm across to case. Then with lockgrips or pliers, turn the actuator arm all the way in/up (till the ram pushes all the way out internally, disengaging the plates) (also check to see that the gears are free in 1st) then mark the case again going off the line thats on the actuator arm. Now you have your spread.
From that spread, you should be able to see the movement necessary in order to properly get enough pull to disengage the plates. Set clutch to match via the lower and upper adjustment screws.
It honestly shouldn't be this hard. DO you know if the clutch has bee messed with in the past? IE has some one added to many plates or is your basket grooved fro wear?