the tommy lift we had is a single fold up . you let it down and fold out a single aluminum plateform it is rated at no more then yours and if you use my idea it will ruin the original plate design but it will lift a gate of any size you need . we used 2'' x 2'' x 1/8'' square on 14'' centers with a 1/4'' plate i would guess this would weigh 700 lbs with teh second fold it lifts and it is totally fine we built it 6 years ago and it still lifts 1000s of times a year. on our second gate ,the one that rest on the ground we did it like a standard trailer gate with 5 braces of 2'' 90 deg. 3/16'' thick steel.