I worked out all the numbers for Savage Attacker on a thread in the "Builds & Optimization" forums. Here's a quick link:
http://www.enworld.org/forum/showthread.php?477385-The-importance-of-being-a-20/page3 It technically focuses on whether it's better to take +2 Str or Savage Attacker, but the numbers should help out regardless.
Also, it's important to note that Savage Attacker greatly favors the 1d12 weapons, while GWF favors the 2d6 weapons. Taking both more or less balances out, but if you decided to drop the Ranger, Savage Attacker would give a bigger flat boost to damage than GWF:
[table="class: grid"]
[tr]
[td][/td]
[td]1d12[/td]
[td]2d6[/td]
[/tr]
[tr]
[td]Savage Attacker[/td]
[td]6.5000[/td]
[td]7.0000[/td]
[/tr]
[tr]
[td]GWF Style[/td]
[td]7.3333[/td]
[td]8.3333[/td]
[/tr]
[tr]
[td]Savage Attacker[/td]
[td]8.4861[/td]
[td]8.3596[/td]
[/tr]
[tr]
[td]Both[/td]
[td]9.0552[/td]
[td]9.4649[/td]
[/tr]
[/table]