yep very good poitn, ive noticed that with machine ANYTHING, its possibly to leverage more weight on one side, at least as long as the mechanisms are connected (you move one side and the other moves as well), so try for more free weights and isolation might also be a good idea. Also mental imagery helps, for example when im doing back, I have to really imagine the back muscles moving in my head to get a good workout, im sure you can apply that to legs somehow--