Nearly correct. 
Code:
"rotation" : [
// Race
{
"TrackId" : "Donington Park National",
"VehicleClassId" : "Touring Car",
"PracticeLength" : 0,
"QualifyLength" : 10,
"QualifyDateHour" : 8,
"QualifyWeatherSlots" : 1,
"QualifyWeatherSlot1" : "LightCloud",
"RaceFormationLap" : 1,
"RaceLength" : 10,
"RaceDateYear" : 2017,
"RaceDateMonth" : 3,
"RaceDateDay" : 27,
"RaceDateHour" : 14,
"RaceWeatherSlots" : 1,
"RaceWeatherSlot1" : "MediumCloud",
},
// Practice
{
"TrackId" : "Donington Park National",
"VehicleClassId" : "Touring Car",
"PracticeLength" : 1200,
"PracticeDateHour" : 6,
"PracticeWeatherSlots" : 1,
"PracticeWeatherSlot1" : "Overcast",
"QualifyLength" : 0,
"RaceLength" : 0,
"RaceDateYear" : 2017,
"RaceDateMonth" : 3,
"RaceDateDay" : 27,
"RaceDateHour" : 14,
}
]
This should do the trick, though its very basic.