Yeah, I can see how it'd be a little confusing. Technically it's non-repeatable, but essentially you can go through the pattern hunt 4 times, once for each piece of RSE.
Personally, I prefer Gusgen Mines as the location when possible. You can check the RSE availability at MithraPride's
Vana'diel Clock. Note that if you can do this as THF main, it makes things easier since you don't have to farm keys.

Kumei, pickpocket of Midgardsormr(Bastok Rank 8)
THF75, DRK63, NIN40, WAR37, WHM37, DNC36, RNG36, BLM20, SAM20, RDM14, DRG12, BRD11, COR11, BST10, PUP6, SCH4
Alchemy 71, Smithing 50, Goldsmithing 39, Leathercraft 23, Fishing 16
Koren, San d'Orian Adv.(Rank 6)
WHM58, SMN32, SCH30, BLM30, NIN23, PLD6, BRD6, RDM5, RNG1
Woodworking 29, Cooking 11
All celestials(Trial-Size)
Myrna, Windurstian Merchant
BLM20, WHM15
Clothcraft 24
Nyamohrreh, Windurstian Adv.(Rank 2)
WAR28, WHM23, MNK18, BLM5