If you're looking for a balanced bitterer (not too smooth, not too harsh) for American ales, CTZ (Columbus, Tomahawk, or Zeus) is great. Likewise Nugget, Bravo, and Warrior are all good choices. If you want something super-smooth, Apollo, Magnum, Summit, and Simcoe are all very smooth bitterers, in my experience.
If it was my beer, I would do something like:
.5 oz CTZ 60 min
1 oz cascade/centennial/amarillo 10 min
3 oz homegrown cascade 0 min
Looks good. Have you bittered with chinook before? It's pretty assertive. I like it, just mentioning it.
Yes, I have, but for a subtler approach, do you have a different recommendation? Cascade pellets?