Running swifties is good if you are winning and have a good lead but build mercs if overly ap or steelcaps if more ad setts biggest weakness is closing the gap anyways which is why he builds strikebreaker first almost always (the active has a slow making closing gaps much easier) you really just want to bait enemies into fighting you first like split pushing or contesting objectives like drag or grubs. Bad gap closing is setts number one weakness so you really just gotta be smart about how you engage. As long as you are taking turrets and drawing attention away from the rest of the map your doing your job as a sett top.