torpedoes are in their own scripts, in the Tactical/Projectiles folder, unfortunately, there isn't a tool for editing them (to my knowledge) so you'll have to open the .PYs.
Python is actually really easy once you know what to look for, each attribute is labeled in plain english, if you're just changing values of existing attributes, you need almost no coding skill whatsoever, you can even tweak the Hardpoints like this if you know what system you're looking for. Torpedoes are really easy to edit, there's only like a couple dozen lines of code in each of the torpedo files that you need to worry about. For damage you'll be looking for the "GetDamage" Attribute. Torpedoes are also modular, you can set any torpedo to any ship by editing the Torpedoes system in the hardpoint.