In regards to the shirt sizing, it depends on the style. He makes regular fit and slim fit and if you are a bit heavier on topthe slim may be a bit tight. Generally speaking though, a size V is good for medium men. For women, in my experience, size I is an extra small but again, it depends on the fit of the particular top. Most of the tops my friend tried last summer (especially those with the crossed open back) were a bit tight and although she usually wears a size II in SS, she had to size up. It's generally better to ask the retailer before purchasing to avoid surprises.