Hi mate, from my experience with current & previous edition of the games it's not about the formation but more about the set-piece instruction.
I always set my set-piece like this:
- in set-piece instruction, set corner delivers to "far post" and free kicks to "cross far".
- in player instruction, pick your best header (combination of player's height, jumping, & heading) to "attack far post" when in attacking corner situation, he will be the main threat and scores many from this scenario.
- then set your 2nd best header to "stand on far post" in attacking corner situation, he will be the one who create distraction for opponents so your main header target will left unmarked most of the time.
- still in player instruction, pick one player (i recommend your forward or winger) and set him to "challenge gk", he will score a lot too through sweeping fumble balls from the goalkeeper after saving shoots from your main header.
- finally, pick one player with good long shot & first touch, set him to "lurk outside area" to score from distance through intercepting clearance from defenders.
With this scenario my team usually have the best rating for goals from corners & indirect freekicks. Here I show one highlight to prove this scenario works
All goals were scored from corners & indirect freekicks.
Hope this would help you