How to start caja using just left half screen with --geometry?

I use caja often with two windows open at the same time, each exactly half the screen. By default, caja opens with a window a bit to the right, not exactly half the screen. The next caja opens a window on top. However, if the first caja window is reduced to half the screen to the left, the next opens in the right half. Thus, how do I have the default location for the first caja open to the left half of the screen? I experimented with caja --geometry=960x1080 . (half my screen in pixels), but it was not doing what I wanted. Two questions: 1. What is the correct geometry value for a screen 1920 by 1080? 2. How do you have caja open in the top left corner?