Please reset the profile to default in the config app. VorpX handles FOV automatically for this game, there is nothing you could improve by tweaking anything manually. If there is still a slight top/bottom border afterwards, then because the game doesn’t allow the FOV to be set higher that vorpX already does.
One thing that might improve things is running the game with a 4:3 resolution. In some games that can allow vorpX to set a higher FOV. For FullVR games that’s good practice anyway since it avoids rendering pixels that never show in the headset.