I don't use weights for leg workouts.
I never use weights with the leg workouts- except for deadlifts.
I am overweight enough that I am lifting as much as I should without weights.
I got a little ambitious and tried in Hypertrophy STS to increase my weight by about 10% over the extra weight I just carry naturally. Since I could do Endurance part I thought that increase made since. This was about 5 lb, or 5 lb in each hand sometimes, really not much extra weight. However, I regretted it because my knee complained about it. I don't plan to try it again unless my knee has a long track record of handling these workouts.
If I loose weight in the future, I will increase my weight proportionately for the leg workout, and calculate a 1 Rep max for these exercises.
I introduced my friend to Cathe. She liked her but stopped using Cathe because she hurt her back using weights on her shoulders for squats. She said she didn't think she should be lifting like that - her body was telling her this but she did it anyway and was injured. It never occurred to her to do the squats without weights so she stopped using Cathe altogether. She said she was too old for these workouts.
I think our body often tell us what we should be doing. It is crystal clear to me not using weights in legs workouts it the right choice for me.
Sometimes I drop the deadlift weights over the calculated value because my low back is bothering me. I just left a little less than the computer says I can, and sometimes I leave off a set if it feels fatigued. If I think my low back is having a hard time, why risk it?