I've heard that 2cc of Rejuran isn't enough to see results. What are the recommended cycle and duration of the effects?

I usually suffer from severe internal dryness and rough skin texture, so I turned my attention to skin boosters rather than lifting treatments, and I am currently delving deeply into Rejuran Healer. After searching through community posts, I found many comments stating that it is difficult to feel the effects after just one session, and that its true value becomes apparent after receiving at least three consecutive treatments. Since the treatment uses a 2cc volume per session, I also saw reviews saying that the effect is minimal because 2cc is too small to spread over the entire face. I am wondering if it is appropriate to increase the volume to around 4cc if I have a large face or many problem areas, or if it is wiser to start with the standard volume and observe the results. Additionally, I would like to know approximately how long the effects actually feel after completing three sessions at one-month intervals, as is commonly said. I find it daunting to go through that painful process three times, so I am curious about the re-treatment cycle: if the effects accumulated previously are maintained by getting just one treatment every six months after the initial three sessions, as a kind of extension.