After a bit of hassle, I decided that in a lot of cases, I got better results from using a simple texture map for the color and bump channels.  It gave me better detail and it was simple to size by using the tile seamlessly option.  I also get much finer control over the brick coloration, detail etc.  If I can remember how to insert am image here I will send up one you can look at that I designed for the new Hotel scene I am working on.