Planning an IWD-style HoF mod for BGEE/BG2EE

So, a very elementary question: is there an easier way to change CRE files in accordance with IWD HoF rules than going over each and every one of the 4600+ CRE entries manually? E. g.: according to HoF rules, the creatures have their base hp x 3 + 80. Do I have to change each monster manually, or...?

PS: Yes, there are obvious exceptions to the rule (joinable NPCs). But I'm interested in the global method, if existant.