I generally go full flaps for all x-wind landings.
X-winds over 15kts I'll think about reducing the flap settings.
With Gusty headwinds or or wind shifts lower flap settings are always a good idea. On the 757/767 you have to concern yourself with flap blow up speeds. so if the IAS is bouncing around you're better off flaps already in/or closer to their blow up position.