You have addressed what I think is an important issue. Yes, when you first begin, you should start out light and build up your tolerance to this new activity. As you learn about the process, you should build your routine up to a moderate level that you determine provides a beneficial result without causing damage.
And now for the important part. I don’t think is is necessary to continually add more force to your routine once you find your ideal workout level. It is, however, what most guys do, because it seems the natural thing to do and you get anxious to get bigger and faster results. What most often results is that guys end up using too much force and causing damage that actually slows down or even completely stalls out the process.
So as far as the use of force is concerned, whether it be jelqing or hanging or stretching or pumping, find the moderate force that brings results without causing trauma. If you want to add to your routine from that point, keep using the same force, but do it for a longer time.