I'm looking at the Google satellite photo of the site. The series of rooftops from which the shots came is fairly long so the range looks to be from 200 to 350 yards. The body of the shooter was behind the peak of one of those roofs so he shot from a defilated position on the former president's right. You can see the people at the top of the bleachers behind the podium looking that way when they get back up. Before they got former president Trump up, the call came in, "shooter down, shooter down," so it was that quick. There are pics of the counter-sniper team who apparently took the sniper out and they appear to be after the shot.
Bob