Great mock-ups. Ideally, K. Rool would have a larger head and slightly larger body, which would require him to face more toward the screen so as to accommodate more of his girth onstage. Basically, as big as it's possible to make a character, he should be, heh.Alright, thanks to @ Thelimomon 's efforts to provide me a mirror image version of his K. Rool fanart, I've put together probably the last size chart for a while (these are oddly fun to do).
Original (readjusted):
With fanart: