Hope you use some jelquing at least for 2 o 3 months before hanging! Its ok to start with any weight you can handle, but, if you start with 10lbs, eventually your dick will get used to it, then you go to use 12 lbs, then 15 lbs, then 20 lbs, that if you want to see gains months ahead. You should start lighter, 5lb in 5 sessions of 15 minutes each, the general theory is that:
lighter weight/few sessions = minimun/no gais = no results
lighter weights/lots of sessions = normal/good gains (depends on your body)
medium weight/few sessions = dependes on your previous routine
Medium weight/ lots sessions = decent gains no matter your past sessions (lighter to medium routine = ok , heavy to medium routine = no gains)
Heavy weight/few session= developing resistance to weight/harder gains
Heavy weight/lots sessions = faster gains/reach plateou faster
If you start with 10lbs, you will train your penis to handle that kind of weight. And when i said faster gains, I mean you will get in 2 months with heavy weights, same gains that you would get in 4 months with light weights, BUT, your penis after 2 months will need more weigth!, and more, and more, reaching the point of “no gains at all even if i hang 30 lbs”!. See my point? :D