I disagree, .006" can make a difference in noise and operation. You will have to decide for yourself what's acceptable. Do you have marking compound? You might have to put it all together and see where the pattern is. It is a lot of trial and error sometimes which is why most people avoid this job.
If you want to get it right, then I would keep trying. Maybe you can take a thicker shim that you are not using and grind it down a few thou. until you get it where you want it. The drive line places all sell shim packs. If you're not in a hurry, maybe look into getting an extra shim pack.
