Its not the recoil that is harmful to scopes, its the deceleration forces or negative G forces caused by the muzzle brake
A muzzle brakes
effectiveness is determined by a few things:
1. Muzzle gas pressure
2. Muzzle gas Volume
3. Surface area in the brake that muzzle gas pushes against
In your case, the 308 has very little muzzle pressure or gas volume so it will not make any brake work extremely well at reducing felt recoil. The brake you are using is about as aggressive as you can get so that will help you but still, the effects will not be dramatic as it would be with say a 300 RUM with the same brake.
As to the scopes, what makes a scope suitable for a muzzle braked rifle is if it has lense supports on both sides of its lenses for recoil energy support and also for deceleration forces support. Other things also come into play, such as scope height over the bore(the higher the scope the more its stressed) and the weight of the scope(the heavier the scope, the more its stressed).
Personally, I would say that your chambering will not harm any of these scopes. If you were using a 300 RUM, I would say only use the VXIII but with the 308 you should not have any trouble with any of them.