99ish dex isn't necessary, I'd say cut dex and get more vit. As a ME priest I do have significantly faster cast than FS priests at the comparable level, despite my gears being focused on power rather than speed, which means they don't have as much dex.
Get flower wings, easiest obtainable higher-DEF gear, even at +4, because at all wing type gears, refine effect applies twice. The 20 MDEF also helps. 500K is needed for the quest and you might also wanna buy certain ingredients that are pain in the backside
For headgear, Wings of Victory is the obvious choice with unmatched DEF, MDEF while retaining the possibility of overupgrade. And not bad looking either.
A (relatively) cheap alternative would be Pope Mitre, 7 def, additional MDEF for acolyte class and cast time reduction makes it ideal buy choice for starters. 1-2m.
As for shield, well, not much choice there until trans. I'd perhaps go for stone buckler for the reduction vs large. Whatever you choose, stick Hodremlin in it. Pretty good all-round reduction card, you can get them for about 2.5m +/- 500k.
Staff of Recovery for weapon, you might get a few from TUing anubis which is what support priests usually do to kill time between parties. And if not, they're not expensive.
With these basic gears you gain a decent survivability at PvM parties and some not-so-high end MVPs.
I'd say forget about WoE for now, as from what I saw, nontrans priests get quickly disposed of by WS, sinX or champs, eventually even LKs.
Get decent PvM gears first, get trans and take advantage of trans-only gears and overally larger HP growth, the HP count of nontrans priest pretty much sucks.
(well, alternatively you can join Retro WoE which is nontrans, but it means additional expenses and let's face it, priest isn't exactly the best moneymaker)
Also, I'd suggest get an archer class for money hunting, on hillwinds you can quickly made a few mil needed for the basic gears I mentioned before.
Or merchant class, go fishing and sell fish, profit quite ensured as they're in demand. You can also fish out some interesting goodies.
Well, I'm not a pro, I just gave it a thought and this is the product of it
ALSO, are you sure you want to stay FS? Aren't you tired of people "pls" and "plz" -ing you? Aren't you tired of being practically a buff/healbot? Wanna kick some undead and demon arse instead? (at least those undead/demons who have one, if that body part isn't present, select a different one of your choice to kick) Join the ranks of ME priests today!
(haven't seen Raine for a while, and someone should do the ME propaganda)