Specialty Grains

I watched Gordon Strong's BeerSmith interview again. He recommends adding specialty grains to the mash at vorlauf. Has anyone tried this? What were the results?

Buehler, Buehler, anyone?

I've heard that adding the dark grains or roasts late will avoid the harsh flavors that you may get from these strongly flavored grains but I haven't tried it myself.

I've added my dark grains at vorlauf with the following grain bill. On the previous attempt at this beer I had the dark grains added in for the entire mash time and it turned out a bit bitter. On the second attempt the taste was much smoother. Granted I do not change the water chemistry so your mileage may vary.

Darker grains = Carafa II and Special Roast. The Carafa II was the dehusked version but that didn't seem to help.

11 lbs 4.8 oz Pale Malt (2 Row) US (2.0 SRM) Grain 1 80.1 %
1 lbs 7.2 oz Caramel/Crystal Malt - 10L (10.0 SRM) Grain 2 10.3 %
12.0 oz Carafa II (450.0 SRM) Grain 3 5.3 %
9.6 oz Special Roast (50.0 SRM) Grain 4 4.3 %