Review on JR Products GSNI 2300 100 Gas Spring by Carl Morgan

I have a 50 lb hatch that hangs vertically. I wanted to rotate it 90 degrees. I bought two springs for £100 (advice from internet). This should mean they can push 200 pounds in total. You don't! I've tried many times to reorder them but to no avail. The internet gave me formulas for positioning, but I didn't realize I was stupid until I tried to calculate the position of the racks. Now I have a lot of screw holes and still can't raise the sunroof to stay up or down! They don't come with instructions.