To try and translate VJS's recommendation into the parameters that you are using, I would suggest that you try changing your 1.8 factor value to the 2.1 that Louie is using. Depending on how that goes, I would try 2.2 as well. I would recommend that you leave everything else as is, unless you want to lower your factor depth to 50.0 from 50.1 as well or instead of changing the factor value. It would be instructive to see what these changes do to your B1 and B2 values, as well as your run time.