How do you do a 43 in mmm and a 9 in lanvin? I'm a 10.5-11 and a mmm 44 and lanvin 9 fit me both identically. can't imagine going down to a 43 on the mmm. The rick in the 44 is roughly equivalent to the mmm 44, lanvin 9 in my experience. all those sizes meant for a 10.5-11.