Missed this thread. I don't want to risk losing a straight back and something go wrong, cause I'm using a giant ball under my feet rather than cables.
I've been doing Farmer's Squats as an alternative to Squats, where you put all the weight you want on one side of a barbell (with the other side lying on the floor, preferably carpet or something to keep it from slipping); pick up the barbell near the end underhand, then hold the barbell near the end overhand, and then squat as normal.