You probably needed longer gas springs of the standard 26" length and at likely 40 pounds rated force (when extended).? this would give a longer moment arm and more force.? That would give 73% more lifting torque than you get with shorter springs of lower force.? One fellow uses 24" springs at 50 pounds and made a youtube of his installation.? That gives him 100% more lifting torque than your setup.
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It looks like you used 20" springs.? I agree with Dave that you should remove the erroneously installed gas springs that came with the trailer.
Brian Hovander