upscaling shouldnt be too necessary, you should just increase your bitrate. i use between 25k and 35k. if you want to increase the encoding on youtube you can actually resize your game to 2560 by 1440 with statusspec https://drive.google.com/file/d/0BxF7tX-pDxZbcTBpZE1QSEJtQXM/view
just install that and use the command statusspec_resolution_set 2560 1440