My main is in NG+7 or 8 (you lose count...). I haven't played him in a while, though, and he's already in the Kiln. With warping and knowing how to run by all mobs, I kind of forget what the playthrough was like. I can tell you the BKGA and GSoA are pretty much the only melee weapons that still do anything, and even they don't do much more than tickle bosses. For bosses, you really need to be stocked up on high-powered spells. I don't know about lightning miracles, but soul spears (especially crystal, obviously) are definitely a good weapon to stock up on.
Maybe I'll load up that game tomorrow to refresh my memory.