I just finished shooting a B+W film and yeah, CTB doesn't make much difference. The only thing that shooting in color gets you is being able to control the image in post by grabbing specific colors and dimming/brightening them.
Just like color, there are no rules for what types of diffusion to use in B+W. Do some test, but generally I found that what works in color works just fine in B+W white. I did use a bit more contrast though as sometimes people blend into the background easier since there isn't a color difference to help the audience separate the actors from the set.
When you use colored light in B&W, you have to think about what effect it will have on the relative luminance of your subject and background. If you have a white and blue striped shirt and you light it with blue light, shoot it in B&W, you will reduce the contrast of the stripes. Light it with yellow and you will increase the contrast. It takes a lot of experimentation before you can really predict this without going to a monitor, however.