Currently you cannot set the colours or sizes for the sun and moon.
The directionality modifiers such as north, or south, I believe they set the Rising direction, and then the setting direction is opposite that.
So the three pages, North, East, Normal sun, Will make the normal sun rise from the North East.
And for your sunset colour, there's a page for that. So if you had Blue, then Sunset colour, your sunsets would be a vibrant blue, You can combine colours in different orders to get different modifiers. I think there's a glitch currently in which Clear modifiers can cancel out your sunset colouring.. I think. If that's the case then you'll need to put your sunset colour after the clear modifiers symbol, because you need to have it in due to an instability glitch whereby you cannot create a stable world without it. All the other modifiers work correctly with it after them though.
To combine modifiers, it adds two together and averages them, and then adds the third, so.. North, North, East, would average the two norths first, producing north, then averaging the north and east, producing north east. However, if you sequence them North East North, that would average the north and the east producing north east, and then average north east with north, producing NNE.
You can use Dark moon or Dark sun. These prevent instability from having not specified a moon or a sun being there, however they don't actually show up as anything, and won't charge solar panels.
. I am really asking to add 2 suns and 2 moons. I want both suns to rise in the east, but one starts and Noon and one starts at End and they have different colored sunsets. I want the 2 moons to rise in the north. I would also like to have one moon colored white and one moon colored black and the first moon starts at Noon and the second starts at End.