I think there is little question that, once you have done it for a month or so, you will be addicted and your balls will love you for the addiction.
For all day wear, I like heavy and heavier weights. For sleeping, can't beat Secretleather Ball Forcer, which exerts torque on the recumbent scrotum. You can increase the length and thus strength of the stretch through the night and the balls will be receptive to quite a bit of hanging weight when you wake up (and also some nice morning wood).And add more weight as the day goes on.
The Chinese ancients have developed a whole set of testicle enhancement and strengthening exercises and you can do these using a modern style parachute. Doing this is also addictive and it strengtens rather different genital tissues tan hanging alone does (but that is good too).
Provided you are careful and build up weights and stretch slowly and consistently, my experience over about 20 years is that no harm will come to your balls and they and you will be stronger and more virile