Finding the cylinder mounting point isnt that hard. First you need to decide where you will need to mount the hinge of the bed. Thats usually at the back of the frame. Then you will ned to make a couple of measurements from that hinge point. Those measurements are the extended lenght of the cylinder and the retracted lenght of the cylinder. You take an adverage of those two lenghts and that is where the rod end of the cylinder will mount on your bed. With the bed at the proper tilt angle, ( the amount you want the bed to lift), you would measure from the rod end mounting point, the full lenght of the cylinder and make a mark. Then with the bed in the fully down position, you would measure the fully retracted lenght of cylinder. From these two points you would draw two circles, where those circles intersect, is where you would mount the base of the cylinder. using this method, the cylinder should fully extent for maximum lift, and retract fully for full drop. I dont know if you can see this drawing on my shop floor. It is how I figured the mounting points for my knuckle boom build. Same principle, well i didnt like that pic, let me try another one, not the right one either, I will have to go to my pics and see if i can download something that shows it better.