I was just messing with this yesterday on my Hunters for Kill Shot and my Dest Locks for Shadowburn. Both are only active when the target has less than 20% health. I was amazed to find that you can simply add them into your normal macros and they don't hang them.
I then went in to 5-box BH for the 8th time this week (I
may have too many toons) and noticed that I was using a lock with the new macro. I checked recount and sure enough, not only did the lock do good DPS, but he had cast Shadowburn three times as well. I updated the lock macros in my 2-step thread here:
http://www.dual-boxing.com/showthread.php?t=32633
I haven't updated the macros on the hunter portion of that page yet, nor did I have the chance to test them out on a mob with less than 20% health, but I'm pretty sure you can use the same philosophy on your hunter (add
/cast Kill Shot to the bottom of your macro) and it should work just as well. No video feed, no special clicking, just uses it when it is up... sweetness!
