It looks like your elastic get nearly loose at the top, which you actually still want them to provide some noticeable force (though not nearly as much as you need halfway up) to counteract gravity. I would adjust that. You want the elastics to be just barely not strong enough to start moving the lift upward on their own when it's fully down, and you want them to be strong enough the entire way that they can prevent if from lowering at any point. Do your elastics do this? They seem insufficient. The common technique to have enough force higher up and not too much lower down is to make triangular connections with the elastics.
Also, you have a lot of excess metal. First, there are some c-channels that extend further than actually accomplishes anything. Second you could narrow down nearly every piece in the lift to make in an angle instead of a c-channel. You could cut the weight of the lift itself nearly in half with these changes. Since it won't change the motors and the claw, and since those are further out, I'll estimate you could cut the torque requirement by 20% or so.