Heleen, I remember seeing your visual before; you are so clever! I just kind of stumbled along with a tape measure and probably wasn't the most accurate, but it was enlightening anyway. I am not 8 heads tall, either. More like 7.5. I have a long head, though, so maybe that is another wrinkle to factor in!
Claire, I need long torso swimsuits, too (even at my height!) which was another reason I thought I was long or average waisted. But in my case it is because of my long rise. Which turns out NOT to be all that long, according to Imogen's test! But again, that may be only because if you begin with the head measurement and your head is long, that could make things a bit wonky. Like you, I have slightly but not extremely short legs.
Rita, petite tops are pretty much always better on me, yes. As for pants, it just depends. Usually petites are too short in the rise for me, and if they are bootcut they will also be too short for PPL. So I have to look for regulars and hem.
But typically, regulars don't fit in other proportions. For example, the hips often used to be too small for me (or the waist too big); nowadays the hips are often too BIG for me in regulars because I have quite an athletic shape.
My favourite skinnies are a petite size, but I sized up so they'd be comfortable. The truth is, pants are my nemesis, period!