Hoser - how close was it?
He didn't elaborate too much, I am sure it is because it was super busy. He just said it was a good beer, but to roasty and is pretty certain that the crystal malt should be Special B. Sorry I can't be more help. For what it is worth, my wife thought they tasted nearly identical and she is my house sensory panel
So C150 and Special B @ at 10% of the bill will impart two unique and distinctive flavors?
They are 2 different crystal malts, so yes. They are made by different suppliers and have a different production process.
C150L is darker and has some roast character to it.
Special B is more dark stone fruit and deep burnt sugar.
What is a suitable sub for Chinook? Will Northern Brewer work for Arrogant Bastard?
If you are wanting to clone Arrogant Bastard, I think it needs to be Chinook. If you are intent on using a different hop, I would think Nugget would get you the closest character to Chinook, IMHO. Northern Brewer is too "woodsy." But, I would just use chinook. It is easy enough to find right now.