Well, while I'm waiting for my knee to heal, i'm going to get everything ready to start this program. I have a chin up bar already. What about dumbbells? I was thinking about getting some of those adjustable ones, but they're pretty expensive. Do i need a pair....like do you use two at the same time during this stuff? And how much weight do you need....25lbs or more like 50lbs. Please note that I am no weightlifter but not a total wuss either. TIA.