Unreal Set the Packaged Game Window resolution

To set the window size in an Unreal Packaged game have these nodes in your Level Blueprint that are called on Event Begin Play:

Then package the game. In your Packaged Game folder Look for WindowsNoEditor/YourGameName/Config/DefaultGameUserSettings.ini

open the DefaultGameUserSettings.ini and edit it like so…

….Adding a custom ResolutionSizeX makes the BP above load and implement this setting. The FullscreenMode=2 sets it to a borderless window in the centre of the monitor. IDK how to change the window position yet.

[/Script/Engine.GameUserSettings]
bUseVSync=False
ResolutionSizeX=1200
ResolutionSizeY=1200
LastUserConfirmedResolutionSizeX=1200
LastUserConfirmedResolutionSizeY=1200
WindowPosX=-1
WindowPosY=-1
bUseDesktopResolutionForFullscreen=False
FullscreenMode=2
LastConfirmedFullscreenMode=2
Version=5