Set Scaled down Resolution in OS X Game

I have Unreal Engine 4.13.0 and I’m deploying to OS X, Windows, iOS, and Android. My problem is OS X. When I try to run the .app the graphics rendering is so slow. I am running Retina Cinema Display and also on my MacBook Pro 15". One runs 2560x1440 the other runs 2880x1800.

The game is running about 15 fps, far too slow. However when I changed to scaled resolutions 1280x720, 1600x900 , or 1600x1050, or anything basically lower than 1920x1200 it runs fine, fps of 35-60fps. My question is whether I can scale the resolution for OS X like I do in Windows, iOS or Android?

For WIndows I use, GameUserSettings.ini and set it
and for iOS/Android I can change device profiles with
+CVars=r.MobileContentScaleFactor=0.5

Is there a way I could do the same for Mac Deployment. I explored the plist, and other stuff inside of the .app to no avail. Also searched all the config ini and couldn’t find anything. Any advice to scale down slow retina?

I finally figured it out. Once you package the .app file you open package contents in your finder. Then you browse to Contents->UE4->ProjectName.

You create a directory called Config, then add a file called DefaultGameUserSettings.ini where you put your desired resolution.

You add this to your app bundle and everything is good afterwards. Changed mine to 1280x720