I just wanted to write something in here as there are no exploits or guides for Talon's Vengence rep that I can find in the general thread.
Yes this is a guide, but it is using a known exploit.
Just to give some advice on what I do, that I have not been able to find elsewhere. Is just kill all my level 110 alts for the tokens.
The reason for this, is I do not want to annoy the guild or friends with such a monotonous request.
I only have one account, so similar to you closing your game window and rotation between kills of your alts for rep tokens per kill.
One point though, each alt will get a 10 minute hunted debuff. The alt will need to be back alive for this to wear off, and DK's with incorrect talent wont count at all.
This is similar to the achievement hunting for Tol Barad and Getting the Warlord of Draenor kills (which I have not seen anyone write on either for old content) among other things.
Again tedious, but it works if you are willing to put in the time to get those last few kills.
Enjoy.