By Lakshmi.Byrth 2015-09-03 07:35:42
Voidwatch will probably be more productive for you overall, particularly if you have a mule.
Alternatively, you can get Wyvern Scales by despoiling them from Wyverns of any type. You have a 5 minute timer, and you can also use the THF Trust that Despoils (Naja?) for additional shots at them. When she despoils, you can resummon her to reset her timer.
If you purely want scales, farming Vouivre's PHs in Ifrit's Cauldron while chainsummoning the THF trust and spamming Despoil is probably the quickest way to get them. Vouivre is a 100% dropper.