Wish I can try one on, but I don't think I can find one around my area. Anyway, I'm around 5'7'' and 145 pounds. I have tried the reeboks one. In terms of authentic, both 46 and 50 works in terms of length. However the sleeve length for the 50 is a little bit long for me. If I had to pick an reebok authentic, I would go for 46. For premier replica, S and M fits me. Considering a 6100 jersey, any idea what size I may fit? Thanks for the help. First timer here.