More ideas for wand-hand (since it's not just holding a wand, it's also the finger development/flexibility/span of casting wandless spells) : could look like someone fluent in sign language (except he won't know any), or plays some kind of instrument (but callouses all wrong), wrist flexes could be like a fencer (but rest of physique/posture doesn't fit) or (again) conductor (but presence not demonstrative/commanding/theatrical enough)… maybe a painter? (then why the faint electric crackle…?) I just like the idea of confusing poor Sherlock with something relatively inconsequential. The scars are probably more interesting, but would mostly come into play if Sherlock saw Loop naked. Which… I'm not particularly anticipating, but…?