At this level id say
http://waronlinebuilder.org/#career=sla ... 67:4068:0: is most efficient for groups without a heal debuff you will kill so little for a full group spec in t4
http://waronlinebuilder.org/#career=sla ... 4059:4093:
Now the problem with slayer is that spec will only carry you so far you need a group and you need good positioning an over extending slayer will be very rapidly dead. Also a slayer needs to run red to kill things a slayer that constantly drops rage wont kill things but on the other foot a slayer who wont drop his rage at the right time will be dead.
Slayer has some of the best sustained single target dps in the game so lets look at some of its abilities.
Inevitable Doom: The source of much QQ, the envy of choppas everywhere and the reason slayers have such over inflated damage stats in sc. It's a single target dot forget the aoe damage part that's all fluff and won't kill anything remotely healed. On slayer this is your back loaded damage its the first ability you use on an opponent and every 3rd ability afterwards that keeps it on target and keeps your dps up if you cant keep ID on your target probably wont drop.
Important things to remember: Each tick has a separate chance to be defended against and will have a chance to proc your procs. ID is also you test establish for yourself what numbers coming from a target can kill then look for those.
Onslaught: Its a nice aoe dot but usualy it's limited to a debuff cover apply it on the way in but do not refresh it mid way through dpsing a healed target its got no up front damage,
Important things to remember: It's a ranged dot so apply it on the way in learn to time it right and cover other more important debuffs likeeeeee
Shatter Limbs: Another source of much QQ the aoe cool down increaser effective against most targets in the game it can be used defensibly when you have to kite off or offensively when your trying to kill healers. You will see people loose gcd's after poping this as they don't notice its been applied attempt to spam and can't. It's best applied offensively right after onslaught, its damage is meh so again try not to reapply mid kill.
Important things to remember: Cover it it will be cleansed
Deep Wound: No good slayer spec in history ever lacked deep wound I tried playing without it once in T3 and I never would again your ability to kill a healed target is nerf without it. So this is your heal debuff another important debuff it also hits really hard.
Important things to remember: Its a heal debuff idk
Incapacitate: Its your knock down you will only use it for duelling or when you need to kite off. Its undefendable and drops rage so its a good choice when kiting off as it help nerf the melee train chasing you.
Important things to remember: Don't use it offensively it will gimp you ability to kill the downed target leave the offensive cc to your tank.
Rampage: Looks amazing on paper but honestly not that useful in the middle of a fight and no premade is gonna give you enough slack to kite off wait for yellow pop > it wait for red > start dpsing by that time your healers will be dog billed by marauders.
Important things to remember: Good for duels with power through slotted also a good rage dropped vs rdps.
Grievous Harm: Its your m3 finisher it hits like a train enough said.
I think that covers most of the basics i could cover other things like soloing or duelling in more depth if you want.