I would say all depends on the type of racing you have in mind (roundabout - widowhood - natural ECT) 6+6+4 would give you a young bird end an old bird end and a 4ft hen section for roundabout ,the same For widowhood .or 2 / 8 ft one for 1 for YB and 1 for natural ,good luck with what you decide to do . Important plenty of ventilation .