When I was a student, one of the most illuminating moments I experienced was while looking at photos of professional flutists embouchures in Roger Stevens book, Artistic Flute Technique and Study. I saw a photo of someone who had a 'tear drop' upper lip for the first time(which is where the top lip is shaped more like a rooftop with a bit more fullness in the middle of the top lip). None of my teachers had the same physical set up as me, so of course their embouchures looked different than mine. Understanding that the tear drop can be flattened out, that the aperture is fine located off to one side, and that ALL of that was Ok was a breakthrough for me. Understanding also that the bottom lip is slightly turned out (angling the air across the embouchure plate and that one plays across the moist inner surface) and that the top lip angles the air lower is also helpful. Every student has their unique physical structures (lip thickness and shape) and teachers must take these things into account when building an embouchure.