Well since i made this thread ,which was more than a year ago, i can now say that i have changed my mind. I can now comfortably play 4 tables of zoom and even think they are kind of slow at times.
Conclusion: If you practice every day by adding some more volume into your game, it shouldnt take much time before your 8 tabling with ease. and thats coming from someone who couldn't even play 4 tables at once.(nonzoom)