Head Retention: Bottled Guinness Clone

I would like to get better head retention in the AG Guinness Clone that I will be brewing. I don't believe that I can simulate the nitrogen infused Guinness but would like to get a nice creamy head. Here are the base malts that I will be using. About 65% Pale Malt, about 25% Flaked Barley, about 10% Roasted Barley and a small amount of Acid Malt. Is there another malt that I can add to get the result that I want without altering the flavor? Or is there something else that I can do? (I will be bottling.)

They make a product called Heading Powder. Never used it, but I've always been interested.

Have you made this beer before? With all that flaked barley, I'd assume you'd be ok.

You can always add some CaraPils or CaraFoam as well - maybe 0.5lbs worth.

What about that hypodermic needle trick? Always works for me...