Google retired the bid by position preference feature not too long ago. However, you can still achieve similar results if you set up automated rules. You won't be able to get an exact 4.0 position with these rules but you can automate them so that Google adjusts your bids by ad position. You would want to set them up so the rules run every day to ensure consistency.
An issue with attempting to target any position is that you don't always get 3 premium ads showing. So with premium ads showing, position 4 would be top right, but without ad position 4 would be 4 down on the right. This is the reason they removed ad position preference.
As mentioned above, automatic rules are the way to go, but try to take into account the above.