Dan, not sure what model it is that you have,but the one I have can hold fat aluminums and slim carbons very snuggly. The top part of the grip holds bigger arrows, if you have small slim carbons, you just push it down farther into the second grip. Here is a pic of mine.

http://i137.photobucket.com/albums/q212/lrhuntr/HPIM1487.jpg

You can see from the picture that these carbons are pushed down farther than the first grip there. The grip above the carbons is the one that holds all your aluminums and bigger arrows. Hopefully this helps somewhat. Kind of hard to explain.