Get Windows and make mods using that.
No, really, if you use Windows it will make your modding life much easier.
You'll have access to better tools - there's no OS X equivalent of many of the tools that can be found in Raven's SDKs. There's no Mac version of Modview or EffectsEd, for example.
More people will be able to help you if something doesn't seem to be working. You'll even be using a version of the game with fewer bugs, and which more code mods have support for.
If you're really too stubborn to just make mods using Windows, you can still make them (often with a little difficulty) in OS X, which is why this site exists. I'll try to explain any Mac specific changes or workarounds needed, but that will be the focus of the tutorials, rather than those details of modding which can be found in any other tutorial - for example, there are many good tutorials at JKHub.