You can never tell until u actually fight someone, what they are like. I am a GB midget 5'4 and when I was younger and lighter(150) I beat the shit out of a guy 6'5 about 265 and another guy 6'3 245. I have also had my worse ass beating by a guy only5'11 and was about 205, he was a bad mofo. I all 3 of these fights I hit first, when I knew there was no way out of it. Size is not the only factor in a street fight. Heart and insanity, conditioning are just as important, oh and who lands the first shot.