I am currently constructing an around the room shelf layout in my office. I agree that is depends on how high the layout is mounted AFF (above finish floor). I have the layout just above the top of my wall cabinets at my workstations so the layout base is at 60" AFF. The layout will be 16" deep with 4'x4' corners with front cut at angle down to meet the 16" sides. If the layout was lower I would have made it wider at about 24" deep. You should determine what is comfortable for you to reach into the layout without having to bend over and strain
Good luck with your layout!