Really sorry, but I just did one of the biggest double-takes I have ever done on this forum.
You are building in Melbourne and seriously reducing the size of the windows on the north side of your house? And tinting them?
This is what you do with west facing windows in Melbourne.
North is where you get the winter heat gain from. That rumpus window should be as large and clear as possible. A very cheap, very small amount of horizontal fabric/timber battens will shade your northern windows in summer, whereas east and west facing windows require more expensive full height blinds.