I am building my game for the iPad in portrait mode, but developing mostly in Windows. I want to see my Game window in the editor match what the iPad’s screen will look like, but I don’t see any option to set the screen aspect ratio to 3:4. I can only set it to 4:3 (landscape).
How can I set it to 3:4? (or otherwise mimic the iPad screen?)
You can set the game view to 3:4 in the game view dropdown menu, but only if you have iOS as the currently selected publishing option. Otherwise you can manually set a 3:4 size for the game view, and then save the layout.
As a side note, I’d recommend developing in OS X, since the ability to use Unity Remote and/or deploying relatively quick builds to the device for frequent testing is invaluable. You can run Windows in a VM if you need specific Windows apps for development.