Have to go with Mike Williams about the importance of being able to judge true angle, as that is all important in deciding whether to head up, bear away, or hold course and sheet out in a gust that is starting to overpower the boat. For Tornado, my way to judge it is by gauging the boat's angle relative to the parallel rippling on the water caused by the true wind, and not letting your senses be dominated by the apparent feel on your skin, and the better you integrate the two inputs from eyes and skin, the easier it is to get a read on the angles during night sails.
By the way, that point of sail diagram (as do all the other ones you'll see published) misdraws the way the jib behaves getting close to run. It will never wing out to the side until you are past run and actually starting to sail by the lee, unless you're holding it out with a whisker pole. Pet peeve, as a sailing instructor I think it lures inexperienced sailors learning from those diagrams into thinking run, and not sailing by the lee (and impending jibe) when the jib wings out.