Hi guys. I asked for the opinion of my ISRC(Introduction to Computer Systems and Networks, the name is translated from Portuguese lol) professor. In ISRC we study computer architecture to the machine level (circuits, 1s and 0s, booleans, Integrated circuits, compression types, and a lot more). My teacher told that winarar is definitely better than 7z. Therefore he advises me to use it whenever as possible, because it has a higher level of compression than 7z.
I can't prove i spoke to my teacher, but i can prove i studied compression - I have a powerpoint(doubt you will find it useful as it is not in English). Anyway, i can tell you guys the book i am studying, as it is all in English.
The final conclusion is that rar is better than 7z.
I believe in my teacher as he is a professional and very experienced man.
However if you don't believe me, there is nothing else i can do. Still, the final decision will always be yours. In this case, it holds on Pyritie, the leader of the project. No matter which method he chooses to compress, i know i did the best i could.