Hi mate, yeah we met at nomad. You will be fine with a small. I will try to wear over a suit - if I can or at least some heavy knits. And was worried with narrow shoulder of this jacket.Yeah over a suit- will try . If it doesn't fit or look silly then will use it as casual jacket. I have 2 over coats one knee length and one full length . So want to experiment a little. Will let you know the outcome. Good or bad.