With all due respect, you HAVE used weight to adjust your trim. For your body type, you are able to keep it mostly centered. If weight is NOT important for trim, they try putting all your weight in a weight belt and see what happens.I normally use jets, but I've also used long fins with scuba. Just need to adjust how I hold my legs.
My exposure runs the gambit, from rash guard/board shorts, to 3 mil shorty, 5 mil full suit, 7 mil one piece with hood, to dry. Its not body type.
My dive buddy and I are completely different "body types" yet, we both dive the same way, weight is not used to adjust trim, just to get us underwater.
You are lucky.
Note that the way YOU are able to dive does not mean that will work for everyone.