Try Zeiss "Room" Office Lenses
Zeiss "Room" Office Lenses are designed for people that work with other people while using a computer. So your maximum distance is 14' and minimum is set to arm's length. This is perfect for a 9' table. The top of the lenses is at maximum and the bottom is at minimum. This will allow you to shift your eyes up and down rather than shifting your head. Which can cause problems with you rhythm. But, be aware, these are not cheap lenses.
Zeiss "Room" Office Lenses are designed for people that work with other people while using a computer. So your maximum distance is 14' and minimum is set to arm's length. This is perfect for a 9' table. The top of the lenses is at maximum and the bottom is at minimum. This will allow you to shift your eyes up and down rather than shifting your head. Which can cause problems with you rhythm. But, be aware, these are not cheap lenses.