Where possible a Sunday twilight card will be moved to day - they are programmed initially as twilight but HRV keep in contact with SKY and if an interstate gallops meeting/timeslot becomes available on a Sunday afternoon, Victorian trots have first preference to move from evening to the afternoon. This is why you will occasionally see a Sunday meeting run during the afternoon.
I would imagine that an afternoon timeslot, in conjunction with gallops would be more appealing to off-course patrons than being run at 7:30 at night in among interstate dogs.
From a club point of view I would prefer to promote an afternoon card kicking off around 12:30 than trying to get people to come to the track at 7pm on a school night. The only issue with that might be if it is a hot day.
As an example I am aware Stawell had been pushing for an afternoon Sunday for several years against a Sunday twilight for their Cup.