I haven't tried that, but I am playing around with an oatmeal stout. Hoping to bottle carbonate over the weekend. I am a little disappointed with my OG, but I either should have told the brew store that I am BIIB, or I should have bought a grain mill. My bad, but live and learn. The bright side is with the low gravity, I might actually have an English style beer.
I brewed an American style porter a few months back, and I used about 15% of Munich to remove some of the harshness. It seemed to work.