For what it’s worth, I ended up “dry beaning” with 2oz of locally sourced, medium roast, whole beans. The beans went into 3 gallons of beer in the fermenter for one week. When I first tapped the keg, I thought I overdid it, the coffee was a touch too strong in aroma for sure, and the taste was too much coffee and roast, what with the roasted barley and all. It came across as a bit harsh. But after 3 weeks in the keg, the coffee has mellowed considerably to the point that it’s more of a supporting actor. The beer is now a Stout first, with a nice coffee aroma. The taste could still use something to balance the added coffee however.
I think if I were to make this again, I would back off on the % of roasted barley and maybe sub in a touch of crystal...maybe even C120...as a way to tone down the roast and bitterness and give it another dimension. (Idea stolen from Schalfly’s Coffee Stout).
Still, a pretty good first try.