I was quite skinny but 5’9" and not so leggy. If they are thigh highs I’d buy your regular size and just let them end a little lower, that looks good. 35" hips on 6’ sounds like you may want to exercise though?

I know that’s not what you are asking! But I bulked and went from 32-30-33 to 38-31-42, and my legs went from 18" to 23". So more conventionally ‘pretty’ proportions and people still seem to think I am lean and slender.