I used your settings. I also had brightness set to 99. The DNR is working because I can see the image get brighter in steps. You may be right on the grabber and software though. I use a Mac with Miloslick and Debut. My Miloslick is the old version and the latest version of 2.0 isn't happy with my OS even though it should be. The new beta version 3.0 doesn't work either. Bill of MS is looking into it. I also am going to try a powered USB hub. I have a 16' repeater cable extension, but I may be seeing too much voltage drop.
I would like to get the MS s/w working so I can do some stacking experiments. I know Astro Video will do it, but they don't have a Mac version. All of my Windows PC's are broken from throwing them against a wall (just kidding). If I have to go the Windows route, I will try that.
I can't change resolution on my grabber, so that might be something else to look into.
Thanks for your input. If you think of anything else, please let me know.