If you place a queen excluder just under a new box of foundation, they see it as a ceiling where the real ceiling has always been, and don't try to go past it.
If they are already using the excluder, they will go through it as if it doesn't exist. One, two, three, or more supers, they don't care once they have adapted to using the excluder.
Having said that, the nearer the brood you can get the new super, the better. If you can get it under one or more of the existing supers, it will be better, but for now, any empty space will help. Maybe slip it on top in the rain, then harvest a lower super or move it down when the weather clears.
No forgiveness needed. Ask anything any time you want. Glad to help.