Hi Locks,
Not sure if this has been posted anywhere already, just thought of it tbh.
You can equip the class trinket (% chance to spawn imps when HoG is casted) and use the Glyph of HoG which allows you to target an area of use.
I was able to spawn about 24-30 imps before they started de spawning.
This enabled 1000 fury within 10 secs of combat (imps casting only) + 10 molten core procs. Which allows demonbolt spec to open with a full 4 stack burst rotation, or cata spec instant 5 stacks of new 4 set.
Anyways enjoy.
Regards,
Dakripple