Well, if you can get the Goblin leader crossbows, they work great on Orcs. Not only do they do more damage, but they will knock them back one. I never tried 12 crossbowmen, but as vital as they are to my tactics, I may try that out sometime. As I often use throwing axes, most of my mercs end up w/ half-decent ranged, anyway. Once I got a crossbow, I stopped using regular bows. The hit chance is just too low. A crossbowman with “bullseye” can be downright scary.
In a single player game, there's no such thing as cheating. It's merely "creative manipulation of the default settings"!