First, the instructions say to start dryhopping at about 10 days after the wort is made. For a 1.073 OG IIPA, I would advise waiting to let it condition for another 7-10 days before dryhopping. This will help to eliminate the off flavors expelled by the yeast in addition to rounder out the flavor. In the end, you'll have a smoother, less harsh beer.
Second, I don't think Winter Spices would mesh well at all for a dry American IIPA with a citrus and tropical fruit focus. Kinda like adding Ketchup to Lemonade IMO. You have a great recipe there. Drink it and enjoy it... don't muddle it up.