When the Hamburger menu is Open, it appears the default is to cover the entire view port.
I've managed to change the Width... but can't seem to change the Height?
Since I have only 3 menu items total -- is there a way to have the Menu Container Height fit to the menu items?
I haven't tried, but it might be possible to make the menu container transparent. Then, add your own container and set it's measurements as you want them.
How did you change the width? Did you check if you can adjust the height indirectly by changing the text size/spacing?