For the rom if you have nightmare and know how to use it, what about going into the chapter unit editor and changing a unit's loadout to carry the divine weapons? It's a cheap shot seeing as you can get the weapons as early as chapter 1 that way, but why not? It would also be possible to give later recruitable characters the weapons, recruit them in an upcoming chapter and then have it then.
It might be what your NOT looking for, but what about using the class editor nightmare module to change the relative class power to 2 or 1. The lower that stat, the more exp the class in particular gains. It would be much faster then grinding, yet could harm gameplay like you have mentioned you don't want. Just a suggestion.
Well, it's time that I shut up as I feel my ranting is neither useful or welcome. --End Transmission--