When multiple airplanes are using the same holding pattern they are assigned different altitudes. Assuming you are all taking off from the same place, to me different altitudes, maybe 30 feet vertical separation, would be best. The altitude you see on your controller is the height above the ground from where you launched, hence you all need to launch from the same place.
As to Sport mode, most people say it is inefficient at full speed, but if you have a very high headwind then you might not have a choice. 25mph airspeed with a 25mph direct HW equals zero ground speed.