On my server hypnotic dust goes for about 15g per and with cata enchants surpassing Mop the mats are semi relevant again. To farm this dust i found the best way was to run stonecore normal on my bear tank. I got a pretty good amount of greens and you are farming the mount at the same time which is why i prefer it over grim batol. The best way i found to run this is to pull everything to where the first boss is and AoE everything down so the boss comes in. Now the first boss is optional but you do need to spawn him to continue so I kill him personally for gold then I just usually ignore the trash in the hallway to the second boss because they are just in nooks and crannys so I continue to the second boss kill him ( secretly hoping for the mount) and then the area between the second and third boss is where the magic happens. I pull everything up to and including the third boss and then i just loot lots of greensthe rest of the dungeon isnt worth it so i just walk back to the teleporter at the second boss