Originally Posted by chickypad
You're going to get a fair amount of bittering from that big load of whirlpool hops. If you're going with that I would back way down on your 60 and 30 min additions, especially using chinook I'd be worried its going to be really harsh (and I'm a chinook fan). Just for kicks I plugged this in Beersmith including your whirlpool additions and I'm getting 279 IBU calculated for a 5 gal batch.
This is true, but it depends on the temperature of your whirlpool/hopstand. Isomerization drops off as you bring the temperature down from a boil, and ceases somewhere around 170 F. This means that if you add your post-boil hops at this temperature, you don't have to worry about such huge bittering contribution from them, but you still get big flavor/aroma contribution.
And I don't trust BeerSmith's whirlpool calculator. It doesn't take temperature into consideration, nor does it calculate the extended contact that your boil hops would presumably have by staying in the kettle post boil. I don't know exactly what its calculus is, but it gives WAY higher numbers than what actually comes out in the finished beer.
That said, I'm still with chickypad on reducing your early boil additions. Stick some of those hops in a time slot where you can actually taste and smell them rather than just be overwhelmed by their bitterness.