Just use a recipe calculator, like Hopville's Beercalculus http://hopville.com/
combined with the clone info found here: http://www.stonebrew.com/news/081201/
Play around with the Tinseth & Rager formulas when designing the recipe.
Might want to research the recent changes. For instance, I believe they're using WLP007 now and the C-15 is the Great Western brand. Heard a rumor that they might be bittering with Columbus too. I brewed something simliar once, but used 5% C-15 and added 7% White Wheat to the grist. I thought it was better than Stone's version.