I only ever leave fin edges square if required for a scale build.
On almost every 3 or 4FNC rocket I round the leading edge and taper the trailing edge to a sharp knife like edge. It really makes a performance difference.
For futuristic rocket types such as a Scorpius, Trident, Star Speeder, or Manta Bomber, I just round all edges. Square fin edges on rockets make about as much sense as blunt stubby nose cones - ZERO.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !