You can get these seals from a quest called "Smoke over the Coast" in Abyssea-Misareaux by talking to Hungry Wolf. (Rank 1 fame is ok.) You zone in, get VS, go to VC3, and spam xbox button thru his text. Set a macro to trade him a Galkan Sausage and bam, you get Cruor, with the potential to get a seal. Here are supposed drop rates:
Bale Seal: Legs (DRK) (7.3%)
Estoqueur's Seal: Legs (RDM) (8%)
Cirque Seal: Legs (PUP) (6.7%)
Sylvan Seal: Legs (RNG) (6.8%)
So far I have traded 48 Galkan Sausages to (+3, 2 stacks, NQ, 2 stacks) in the last 48 hours. The drop rates seem somewhat correct, but there were lots of times I didn't get jack.
In seals I have gotten:
5x Sylvan Legs
5x Bale Legs
3x Estoquer Legs
2x Cirque Legs
Since I play RNG mostly, 5 sylvan seals in 48 stacks is really not that terrible to me. Just need 3 more and oddsd are, it will take about 2 more stacks of Sausages.
I tell you though, its like a sausage factory up in here. Goodluck!