The "no-conversion castling" seems to be rather odd, but you can fix this by flipping the rooks upside-down at the start of the game, then if something happens that keeps them from castling for the rest of the game, flip them right-side up again to signal that they can't castle anymore.
The "no-conversion castling" seems to be rather odd, but you can fix this by flipping the rooks upside-down at the start of the game, then if something happens that keeps them from castling for the rest of the game, flip them right-side up again to signal that they can't castle anymore.