Interesting, I will have to try it out. Do you mind if I add that to the demo guide I am doing?
I've been playing with Agartha mostly, and gave Atlantis a spin. Agartha is nice and I've been playing with W9/E4 Olm. I've had him to be Dormant, and so far I haven't yet figured combat use for him.
The Defence and Reinvigoration bless is nice for the clumsy Agarthans, but is it the best one? Hmmmm, I do not know.
Rhuax Pact is a great spell if you shoot for Conj 3. Even a lucky Earth Reader can cast it and it produces a good number of Magma Children for 2 gems! It's not hard to mass fiery taskforces which can defeat and rout largish enemy forces.
Did you try out Oreiads with early Arco? They are freaking awesome. One of my faves from new things. Assasin/seductres with 2A along other magics. 2A means you can shoot Lightning Bolts in those commander vs commander battles and I've had an Oreiad kill a mounted commander who drove up to her and then just oogled at her while the Oreiad cast Lightning Bolt on him.
I'd give them a Pendant of Luck for extra security.