Clutch Múspell Summoning

So this banner was fantastic for me and lifted me up a bit after an unlucky CYL2.

With ~150 f2p orbs:
I got a Laevatein pretty early, followed by pity breaker Mia and Ares. With my last 9 orbs I clutched out another Laevatein AND Laegjarn (my main target for the banner). And I got 3 more copies for my Eirika project.

Which IVs for Laevatein?
-Atk / + Def
- Def / + Res

I'm leaning toward the + Def one, as she'll have an incredible 46 Def after buffs; however, I don't like the - Atk.

Also, how has your summoning gone so far?