I am trying to follow Walt Wright's Nectar Management approach (checkerboarding system) exactly on my hives. He uses one deep and two shallow supers for brood. I've got 2 hives that have drawn out most of the deep box, and they neeed supers added. Also, they are Russian queens, which, by reputation anyway, like to have plenty of room before they draw comb and to prevent swarming.
I have always heard to add one super at a time. However, would it be a mistake to add two shallows at once, since that's not much different than adding a sngle deep? Both shallows will hopefully be devoted to brood, so I don't really care whether they go up before they go out. Does this make any difference?