I am wondering what is a good amount for Slow and Heavy Legs. I realize that Cathe is using 50 pounds for squats and lunges, but I am wondering how much I should be using. Cathe is a much smaller woman than I. I am six feet and weight 155 to 160. I am currently also using 50 pounds and feel I can go up another 10 but wonder if that is too much---hard on the back etc. I do not have a "spotter" and will not have one in that future (that I am aware). Maybe 50 is enough? I do not have the genes to allow me to be muscular so that is not an issue (and I am one who wishes it were---always wants what ya can't have). Any input would be wonderful. Thank you!