I've got to ask... why use Premiere for 3d? I love Premiere but I've bootcamped my Mac and loaded Windows 7 and Edius 7 for my 3d work. Edius is just perfect for 3d. Premiere, unfortunately, isn't.
Simply put, we don't have Edius. We have Premiere and FCPX. Should another system prove much more effective we would invest in it, but as I understand it, Premiere's 3D works fine and can easily deal with 4K .r3d files direct from camera.
Sure, Premiere can deal with r3d footage just fine but it doesn't have any native 3d tools.
I've used Tim Dashwood's Stereo3D Toolbox in FCP 7 and dabbled with it in Premiere (the new version supports Premiere, not just After Effects) and it's very good. If you want to do any post-convergence or floating window work (or even digital zooming) it's essential.
Still, I prefer the Stereoscopic Adjuster filter in Edius. Have a look at their 3d QuickStart and you'll see what I mean: