Originally Posted by Walker
Not a lot of advice to give, but I wouldn't necessarily be trying to counter the sweetness of the cherries with IBUs. The sugar in them will ferment and won't be sweet in the beer.
Agreed, I would reccomend bittering hops only, skip the willamette completely, the flavors from the hops will conflict with the cherries IMO. I've made a few fruit beers (Used cherries once, and raspberries twice). I always wait until initial fermentation is done, then toss in the fruit, and fermentation starts up again. I let it go for another 10 days or so then rack to secondary for about 2 weeks then bottle (or keg if you prefer). For the first 3 or 4 weeks the fruit flavor will seem sour. At 6 weeks the sourness will wear off and the flavor will be awesome. In my experience the peak time to drink is from 6 to 14 weeks, after that the fruit flavor starts to fade away. YMMV
Edit: In my cherry beer I only used 3 lbs and it didn't have enough cherry flavor. Not sure how much your cans weigh, but I'd shoot for 6 lbs minimum for a nice cherry flavor, and I can see where using 10 lbs would be very nice. Raspberries were a different story. I used 2 lbs in one batch (porter) and 3 lbs in another (brown ale), and both had very nice raspberry flavor.