Re: water settings.
I recommend:
Refraction - medium
Reflections - medium
Physics - 1/4
At low settings, refraction is an issue and looks poor. At medium, it looks good. Above that is seriously diminishing returns. Even the reflections look just fine at medium. Bringing the water settings up to High yields a 10% performance loss and not that much of an increase in visual fidelity.
Physics at 1/2 are a bit weird. They're over exaggerated. At 1/2, whenever you enter a body of water, you'll see a big massive ripple that looks weird. At 1/4, it's far less pronounced and looks fine. At 0, there's no reaction. Anywhere above 1/2 incurs significant performance loss. Avoid at all costs.