Lunatic Fringe, Red Rider 1981

Normal Sudoku rules apply. SKYSCRAPER SUMS- Numbers in the grid represent buildings of that height, at that location. Smaller buildings cannot be seen if they are behind taller buildings. The numbers outside the grid show the SUM OF THE HEIGHTS of all buildings that can be seen from that location, looking orthogonally into the grid. KILLER CAGE CLONES- The two cages have the same numbers, in the same locations, as one another. The numbers in both cages sum to 18. GERMAN WHISPERS- Numbers on green lines are at least 5 apart from their neighbors on the line. DUTCH WHISPERS- Numbers on red lines are at least 4 apart from their neighbors on the line. Numbers do not repeat on green and red lines.