A little carapils helps. I've used large amounts of flaked barley and oats and not got that fine cream head. Just 4oz makes a big difference in the head of my stouts. I think I prefer Best Matz caramel pils over the Briess carapils. I get even more mouthfeel from it.
try leave a bottle in the fridge for a month or two before opening, that should help with the fine bead you are after if you are thinking Guinness then a nitro setup is needed.
My latest stout uses a couple pounds of flaked barley. Pint glass usually pours to about 3/4"-1" creamy head and it hangs on with at least 1/8" through the entire pint with the glass sides a lacy (sp?) as a new wife's wedding night lingerie!
I had that same problem with lower gravity stouts and even with wheat beers. Dry stouts with 20% flaked barley, wheats with 60% wheat, and even oatmeal stouts with over 10% oats. Protein is not the problem. It's dextrins. Somehow my 60 minute single infusion mashes just did not leave enough. A touch of dextrin malt fixed my issues. A shorter or higher temp mash could help too but my attenuation is just how I want it.