Question / Help how to setup game capture like a speedrunner

[pillz]

im trying to figure out how to adjust my game capture to 90% of the screen and add livesplit to the other 10% while maintaining its resolution but everytime I adjust game capture I cant figure out how to crop it to the right side and still stay fullscreen resolution itcuts off some of the game. please help I linked a picture of what I want the game capture to look like with livesplit