Thirtysomething debuted Sept 29, 1987, on ABC and within a year had won an Emmy for best drama series and was on its way to becoming more than a show. It turned into such cultural phenomenon, the title made its way into the dictionary and, subsequently, into TV history.
The difference between a tornado watch and a tornado warning means the difference between taking action or taking precautions. A watch means that conditions are favorable for a tornado to occur. A warning means that a tornado has been seen or picked up by radar. A warning requires you to take shelter and brace for a potential tornado.
Let's discuss your question first. There is no specific hand-size-to-watch-case diameter ratio, but you should make sure of a few things. First, ensure that the lugs of a watch (those things that hold the strap) don't extend over your wrist when wearing the watch. This can vary a lot because the same watch case size can have a lot of different lug sizes. The opposite is also true.