I've got a long and exciting story about farming this recipe (happened to me earlier this week)
Hope to post it in a separate thread when I'm able to create it
If you use a twinked prot pala tank and have a healer that knows what they're doing you can do RFC in under 5 minutes each run. If you have a full twink group rep grinding it's even faster.
IMO:
prot pal, resto druid, arcane mage, combat rogue are good specs for mass killing through RFC.
Just got it today for my alt after a few days of farming. It eventually dropped from the pirates in DM. Some people recommended farming RFC for it, I'm not so sure about it tbh, since I did a total of 90 RFC runs without any luck. I did around 170 dungeons overall, and around 15 of those were DM (where it actually dropped.) However, Agility recipe dropped a total of 5 times in RFC and once in SFK during this farm.
Me and the RNG haven't been very close friends for the last couple of years though, so that could very well be the reason why the result from my RFC runs turned out the way it did.
Good luck with farming it! Hopefully you wont endure the same horrible farm as I did
Theres a Named Raptor above ratchet for an quest, he got a quiet fast respawn, espiacially when you skin him, got like 1 swiftness recipe 3 deviat supreme recipe and the elixir thingy wich gives 8str and makes you bigger while farming leather