Thanks for the tip Contempt/Point_Man. The rigs got so many things to adjust that I've probably missed a lot of areas that can adjust etc. I'm also still confused as to what to do with the internal cummerbund myself.
I have the internal cummerbund around my lower torso when wearing the vest. I have it fit firmly. Anyway, I believe it's to keep the vest from rising when running or jumping with the weight that it's carrying. Keeps everything in place; acting like a pistol belt.