Viper Sting definitely works
It's a percentage drain,, and unless something is broken here, does seem to work out to about a 4% drain of mana per 15second interval. I don't recall what her total mana was, but if it's in the 1M range, then you're effectively draining ~2670 mana per second with each sting, for an otherwise only recovery shot for the hunter, which isn't bad. - this may or may not be capped by my mana recovery (8% of ~16k with raid buffs means 1280 "mana damage" / recovery per sec). In either case, I believe this to be better than the normal dps that my serpent brings to table, even with 2 piece tier 9.2 bonuses.
In 10 man, two dps on deathwhisper while the rest of the group was addressing adds, we took her shield down to 10% mana remaining in just over 4 minutes. I had viper sting up roughly 90% of the time. This was second attempt at her and last for night due to various reasons. I'm thinking since I believe viper now stacks in 3.3 and it may be possible to confirm if we bring a second hunter in for the fight, and the mana shield drops dramatically sooner.
Just to note, I wasn't only doing viper sting, I was obviously hitting my otherwise normal Survival shot rotation (swapping out viper sting for serpent sting)
Please feel free to correct me where I've gone astray.
I see - my per second math is the fault
thanks Vaelia -
Just a side note/question, is there a recount stat for mana drained or any way that I can go back to my stats from last night (since I haven't yet reset) in order to determine what the actual numbers for the fight were?