How do buttero side zips fit? I'm like a size 11.5, take 46/47 in Guidi, 45 in CDiem and 45 in Layer-0, 45 in CP's and 45 in MMM sneakers / boots.
They fit about a size large, in my experience at least. You'd probably be safe going down .5 as well.
I wear a 44(TTS) in Margiela, and 45 in Guidi. My Buttero's are a size 43 and they fit perfectly. If it helps, my F+B Elfs are also a size 43 which also run a size large.