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.
Bottled: Blackberry Mead
On Deck: Pilsener, Brown, Barleywine, Coffee Porter