With a 1 1/2lbs of RB I don't think any amount of aroma hop will come through. Stouts aren't about hops, they should have a Roast forward taste and good body. IMO, just bitter to a BU:GU of 1 for balance and you will be good. I use Chinook in mine. I have a 20 minute addition of Goldings in there and can't even taste it over the RB.
Kegged:Kolsch,Motueka Pale Ale, Coffee Porter, 3C's IPA
Primary #1: Simcoe/Amarillo IPA
Primary #2: An experiment