I still haven't found a better base stout recipe than BierMuncher's Ode to Arthur
If you want a dry stout, use WLP007, it'll pull any sweetness out.
If you want something a little sweeter, use WLP004.
If you want really sweet, ditch any acid malt and add some lactose.
If you want less bite in your dark grains, add them at vorlauf, or cold steep them the night before and add that to the end of the boil.
My favorite iteration of Ode to Arthur used WLP004, dark grains at vorlauf, and I pressure fermented it in a corny at 7psi until it was done.
It was amazing, and had so many more subtle tones of caramel, toffee, chocolate and espresso, with no bitterness than when I fermented normally.
p.s. A stout without roasted barley is a porter.