It's really all about your tastes. If you like a lot of late hop character, then bombs away. If you want more balance then 0.5-1 oz at both flameout and dry hopped paired with 25-35 IBU's at either FWH or 15-20 minutes is a good place to start. Columbus can give a pretty sharp bitterness when used at 60+ minutes, so you may want to steer away from that. A beer like this works pretty well without a traditional 60 minute addition.