Thank you for the reply, Checkmate!Hi! Arya,
I use the weight I can do 20 to 30 reps for failure. When I can do 30 reps I increase the weight. With these excercises I started with 15lbs three times a week. For the Standing Row, I'm up to 40 lbs per hand and can do 22 reps. Weighted Torso Twist I'm up to 25 lbs & 28 reps.
I'm working for stamina not strength and it seems to be working. Make sure you start with low weight and work your way up.