The brew store inventory decided it for me: I'm using California Ale Yeast for the Imperial IPA. I no longer need to worry about the attenuation of this beer. It will finish dry, allowing the bitterness to assert itself on what I hope is an interesting though-not-sweet malt character.

About the hops, I'm of a different minds. What I've been considering mostly is magnum to bitter, cascade for aroma and cascade and willamette for flavor, with an emphasis on willamette. But I still haven't settled. I'll probably go buy the ingredients today, so we'll know soon what the recipe was.