Depends on which DD cause tp bonus may or may not matter. Dark designs, Deluges and Latitude, unless you already have a bunch of TP bonus.
Then swap to Coercion Deluges Exhortation Unless You're using Nyame
Then swap to Coercion Deluges Tropics(?)
Atmacite of Coercion - Regain +30 Kaggen
Atmacite of Dark Designs - TP Bonus +500 Abununnu
Atmacite of Deluges - STP+15 DA +3% Uptala
Atmacite of Exhortation - SC damage +30% Qilin
Atmacite of Latitude - TP Bonus +500 Pil
Atmacite of the Tropics - "Triple Attack"+3% Yalungur
For a healer it really doesn't matter. You don't need refresh, or cure potency or fast cast or anything really lol. Maybe I would use things with Sphere to boost the DD.
Atmacite of the Depths - Sphere: "Double Attack"+2% Bismarck
Atmacite of Exhortation - Sphere: "Regain"+20 Qilin
https://www.bg-wiki.com/ffxi/Category:Atmacite