As PeterC has said, you know when your AGM should be each year give or take. So if it is usually held at the end of May, send your motion in mid April. And do send copies to EC, SM. If you want more people to be involved other than those on the EC, why don’t you put a note on the notice board telling everyone to put in their own motions for the AGM.
Our AGM’s have been held in the same month, on the same day, about the same date for 12 years. And yet still, we have owners who come to the AGM with their motions. This despite the fact that the agenda is sent out well in advance, plenty of time to add motions. I have given up on my complex. But try to get the message across to owners in yours. They may be more responsive.