Dread Fort, Casterly Rock, Highgarden, Red Keep, and Castle Black. I'd add Riverrun, but with that target painted on the side I have a feeling it won't last long.Which are those castles?
Because if you don't remember Riverrun, let me tell you that it is a) a thing and b) not involved in any plans.
If I was making actual tactical or strategic suggestions I'd have read over the maps first, but for castle nuking shitposts firing from the hip seems fine.