try using ninjutsu skill+ gear with San spells, broke 260 dmg with hyoton, raiton, and katon San on a few mobs, mostly too weaks, on tougher mobs still have done 180 before.
Man i just got mine a few days ago, was all exited at first. Then i decided to test out the "enhances ninjitsu damamge". Man talk about dissapointing. With no ninjitsu gear on my hoyoton would do 131 to a too weak rarab (Ulegard range, so it has enough hp to live through 2 casts). I put this thing on, what do i get, frikin 137 damage. I was in utter disbelief. I tried the same thing on a good dozen more rarabs, same numbers, koga give +5 damage on a too weak >.>
This thing is only good IF you have parry capped and its nighttime, or to run around going, "look, i got relic gear."
I'm curious still. Could it be, that the effect also lowers the resist of the next element even more? Like our ninja merits...? If you used only one tool, you wouldn't really see. Try using the whole wheel and if it does overall more than 42 damage (the extra 7 damage X 6 elements), then it's a lot better than it first seemed.