I have an 8 month old female who I want to start in weight pulling or at least keep her in shape. She's about 42.5 pounds right now, and was wondering what would be a good weight to start her on? Right now I walk her with a 5 pound weight collar for about 30-45 min just on our normal walk, I know it's not alot, just getting her use to having weight on. But after I get the harness I ordered what would be a good starting weight. Or should I just start with empty milk jugs so she gets used to having something behind her? Thanks for you input