You're talking with the biggest nerd when it comes to bg's keep that in mind will you, I've done this many bg's as of now
http://piclair.com/data/agtoz.jpg (4299)
and I can assure you that camping the GY will give you the most amount of kills unless TP (unless there's 1 bot on the alliance side jumping down all the time). I've tested running around healing random 115k hp people that are far away from the graveyard but Abbi will forever get more HK's. Why? Because Abbi will go to wherever the kills are.
Changing gear to ruthless will absolutely make it harder but will also slow down the HK farming. It's not something that I will do.
I've done enough bg's at this point to know what works and what doesn't. I know how to farm them kills.