I aim for getting most of my bittering from the bittering hops. 90 mins is max for getting all IBU's from the hops, I generally go about 75 mins and put the bittering hops in after first running, to get a good utilization.
Flavor at 20, and a bunch more at flameout for aroma. Very little IBU's come from the 20 addition, none from the 0 one.
Adjust amounts and boiling times to make changes from varying AA% of same hops than was in recipe, or to use an alternative hops choice.