1 Imperial English
Ale Yeast.
The key to making a great clone is using roasted unmalted barley (or black barley) with a color rating around 500 °L. Do not use roasted barley (300 °L), roasted malt (500 °L) or black patent malt (500 °L).
To get that "Guinness tang," try this. After pitching the yeast to your stout, siphon 19 oz. of pitched wort to a sanitized 22 oz. bottle. Pitch bottle with a small amount of Brettanomyces and Lactobacillus. Cover bottle with aluminum foil and let ferment. When beer in bottle is done fermenting, pour it in a saucepan and heat to 160 °F (71 °C) for 15 minutes. Cool the beer and pour and pour it back in the bottle. Cap bottle and refrigerate. Add to stout when bottling or kegging.