Have you tried stiff legged deadlifts? I used to do them all the time then went to standard ones for my back. On saturday (squat day) I decided to do stiff leg dl for my hammys but I think my form was off because the next day my lower back was sore, maybe I was leaning over my toes too far or something?... do you feel it in your lower back when you do them? I always thought they;re more for your hamstrings.. was considering doing good mornings again too.. what do you do for your hams?