Slinky
Busiest time of year - Summer.
Weekdays tend to be busier than weekends, with all the business shuttles up and down the country and to the European hubs, in terms of time of day, we get busy with Long-Haul arrivals from 6am, then its pretty much solid all day till maybe 9pm where it starts dying off till 11pm ish. Varies day to day, and if theres bad weather then it starts getting interesting...
In terms of traffic controlled at once... anything up to 20 a/c in GMC, i suppose 7 or 8 in arrivals and again 20 or so in departures.