I contacted Camden Town Brewery last week telling them that I wanted to clone their beer and they were very helpful. Somehow I managed to delete the email as soon as I read it. They confirmed that the Magnum is only for bittering and they get about 20 IBU's from it. The rest of the IBU's are made up from equal amounts of MOSAIC, CHINOOK & SIMCOE in the late boil. They dry hop with all three hops at about 5.5 grams per liter. However they don't use an equal amount of each one of the hops they use 2 parts and 1 part each for the other two. I'll ether email them back or make a guess, I've got a week or so before I need to worry about dry hopping. Anyway I'm going to go with the following: