Stunner is crap, BHP are awesome, >here's a video, and here's a screen of a realistically (not ideally) equipped BP on my test server (+3 foods)

For equip you should focus on str/aspd/crit, cards like Sanin mentioned are useless/unobtainable assuming a reasonable 99 server. Non-crit builds are really good utilizing signum crucis as you briefly see in the video above, and there's a ton of demon/undead specific weapons/equip for priest available.
Quick note about your SS, you are using a double smashing spike, one Orc Lady gives +30% to orcs, so damage won't be as high because it would be +40% total, and can I ask a question? How does the Priest avoid a major hit from knocking him/her out with a few Vit and only a racial shield? I mean, to level from Priest to Rebirth, that priest isn't relying on much defense nor flee, Healing would cost some pretty big deal of SP for solo upkeep, so is it by potting?
And also, if the server TC is playing on has Mid-Gear[1](iRO Chaos,Loki and Iris have them), then Vanberk helps a lot, it gives 2 STR and a chance to greatly increase crit.
PS: Wtf is going on back some posts with Solace card? BPs rely mostly on Agi,Str and in some occasions Crit, they have low INT, not to mention a lowish HP a vit-less BP would have would make him pretty much suicidal, and why were people saying to put INT? it would just make the overall DPS crappier and turn the BP into a crappy BP/FS hybrid