Thanks again everyone. Still haven't had a chance to do this but right now I'm leaning towards trying just a 30 min intense boil and then hopping only at 10 mins and a huge hop stand, likely lid off. I'm doing 18 gal boils so I think the thermal mass will take a very long time to drop below 180 unless I crank the garage door open. I know in the past I've overshot my bitterness due to long stands. It's only going to save 1/2 an hour so I don't know if it's worth the effort but I need to save as much time as I can.