Just tested this out on my hunter, (Works 100% but instruction are a little tricky to get at first but you will understand when you get there.
Farming Results -
Hour 1 - (Note I died quite a bit getting use to it) I was able to kill 20 Twisters. Recieved 200g~ and 1 green and some Embersilk.
Hour 2 - (PURE LUCK) I was fortunate to receive 2 Chelleys staves. One sold instantly for 17kg in trade and used other on an alt.
After 2 hours I was tired and stopped, but your roughly get the picture, the drop chance is roughly 1 per 33 for each item, 3%, (I am no math wizard and dont know the right formula but w/e) 7 things can drop, with 3% for each You could say that almost a guaranteed drop per 25 or so kills. Well worth farming but you WILL get very frustrated with dying alot.
Was done in brand new 85 greens and blues doesnt require much gear to complete.