It really isn't going to matter with factory ammo. A 1in10 twist barrel will stabilize anything that you will shoot out of the .308.
But basically the longer the bullet is the faster the twist rate needs to be in order for the bullet to be stable... especially as the range increases and the velocity decreases. Velocity also matters. As velocity increases the less twist you need in a barrel for the bullet to be stable. This is because as the velocity increases (going from a .308 to a 300 mag) the bullet also spins faster even though it is still making one revolution per "X" inches.