Ideally SCH would benefit the most from SpS damage over the other healers just because of the amount of dots we have, compared to AST which has just one.

I'm using the i340 Augmented Lost Allagan Codex until I get the Genji Codex (PIE/Crit) to drop, or when my raid lets me roll on the weapon box. My white mage and I were the most screwed in the group with nimble savage gear drops, so they let me have a weapon dip upgrade. Since more weapon damage>substats, and honestly it's not like SCH is struggling to get better substats because there is pretty good gear savage and tome-wise to get Crit. Don't forget a higher ilevel weapon gives more VIT too, that's pretty valuable in savage.

Don't really need to fish for crits though, sure it's nice to get a crit deploy for O4S Almagest, or flares. It adds up to more DPS since both can heal less but it's not a game breaker.