If I do a hop stand (letting my aroma hops sit in hot wort, around 180F for 20-30 minutes), how much extra bitterness will I get from the hops oil in the wort from the bittering and flavor hops? Will it be negligible?
According to John Palmer, hops pretty much stop isomerizing under 180F, so you'll be adding very very little bitterness with that hopstand. That's almost exactly what I do (175F for 45 minutes) and it works every time. I think you're totally on the right track. Though why not bump up the time a little bit.