Adamantoise - 5500
Balmung - 18500
Cactuar - 8750
Coeurl - 4500
Faerie - 8000
Gilgamesh - 15000
Goblin - 3500
Jenova - 6500
Mateus - 2500
Midgardsomr - 6000
Sargatanas - 8500
Siren - 5000
Zalera - 3500
(Rough estimates etc)
Most likely candidates for 'designated' server to get bonuses are: Goblin, Mateus, and Zalera.
Siren is not too likely. Sargatanas for sure will not get it. Jenova may not either cause it's close to that 7k = highly congested.