In real life, most hunters in North America follow the Boone & Crockett (B&C) scoring system when it comes to scoring big game.
For example, for deer, they are scored based on the width of their spread, length of each point and main beam, the girth of their antler bases, etcetera.
I would highly recommend looking into the B&C scoring system, as it would definitely help the game immensely.
Older games like theHunter Classic and Deer Hunter: The 2005 Season use the B&C scoring system, so why shouldn’t a newer game use it?
Additionally, the CIC Trophy Evaluation system seems to be the popular method in Europe, so it would also make sense to incorporate this as well when it comes to European species.