For my pale ales I start flavor additions at 20 minutes left in the boil.
Depending on how many IBU's and how much flavore you're going for, try alternating .5 oz each of the Amarillo and Cascade at 20, 15, 10, and 5 minutes.
Secondary: 8/8/8 RIS, 9/9/9 Barley Wine
Kegged: Robust Porter, Oatmeal Stout, IPA, Centennial Blonde, Yooper's hoppy amber, Blue Moon Clone.
Upcoming Brews: IIPA, SMaSH, Black IPA