It's very important to allow your penis time to develop tissue maturity via the conditioning process. I have said this countless times.... it took me three full months to go from 3 lbs to 8 lbs.
If you feel you can do more weight then that decision is up to you. Weight hanging is an intuitive process, you're learning what type of work load your penis can handle and more importantly what it requires to reach fatigue.
The theoretical assumption that going too heavy too fast can make your penis stronger and cause it to prematurely adapt to the work load and inhibit gains is purely speculative. It might have some merit, but nobody knows for certain if that is true. If they can say this without any reservation, I would ask how can you prove it?
As for how much weight you feel you can hang with at this time, is a decision only you can make. It's all based on how you feel and respond. You will eventually get to a place where you cannot go any heavier. So to me it only makes logical sense to make gradual increases and focus on achieving fatigue and learning how to relax your pelvic floor muscle while you are under traction.