I'm really enjoying an IPA I just brewed using these three hops in combination for flavor/aroma. I used 1/2 oz of Chinook at 60 minutes for my bittering charge, then I used 1/2 oz each of Simcoe, Amarillo and Citra at 15, 10, 5, and flameout. I did a 30-minute hot steep/whirlpool. Then I dry-hopped with 3/4 oz of each. The main notes are the tropical fruit from the Citra highlighted by some floral notes from the Amarillo. The Simcoe gives a nice resiny bite and adds some real nice complexity.
My recommendation is to get rid of your 30 and 40 minute additions (and maybe even the 20-minute one). Add those at flameout and do a long whirlpool before chilling. At 30 and 40 minutes you aren't getting much flavor or aroma contribution from those hops, since most of the hop oils will boil off. You really want to add them as late as possible. I'd also dry hop with at least an ounce of each of the hops.
The more hoppy beers I brew, the more simple I keep my hop schedule. For my next hop bomb, my hop schedule is probably going to be something like this:
60 min - 0.5 oz of Columbus or Chinook
10 min - massive addition of a blend of all my flavor/aroma hops
Flameout - another massive addition of the hop blend
Dry hop - split the remaining hops in 3 batches and add them each 3 days apart. Bottle 3 days after the last addition.