You can get Rama’s plugin from: https://forums.unrealengine/showthread.php?3851-(39)-Rama-s-Extra-Blueprint-Nodes-for-You-as-a-Plugin-No-C-Required!
His plugin has a ‘get screen adapter resolutions’ blueprint node and a picture somewhere in that thread on how to use it.
Just be sure to mention him somewhere in your game if you end up using his code 