[Radio_man]

I can see the new presenters doing longer hours than currently

Not necessarily - assuming Outside Source is still kept on at 7pm, the daytime 5am - 7pm weekday schedule can still be broken down into 4 x 3 hour and 1 x 2 hour shifts.
The main unknown is what shift Christian Fraser will do - whether he'll stay on The Context for an hour at 9pm or if he'll be moved into the weekday daytime schedule.
If he does stay on at 9pm, we could have a presenter/reporter doing a weekday daytime shift.