I don't know. I've always just done 45 down, mend and let it ride.
I'd rather dead drift a seam. I typically swing where there's a natural greasiness to the water/upwelling current/tailoutish. That being said, sometimes I will dead drift the gut and then let it swing at the end of my drift.
Those are the spots imo where a bug would be able to start acending. In a turbulent seam, I'd think they'd just be getting washed around.
I'd like to hear what others say, though.