Thanks for this! It's actually a really good idea..
FALSE, the game has been out for months now and this obviously isn't the best way to get headshots... Your best shot is to either boost, as one person has mentioned, get good at the game so much that your thumb-pad control is so smooth that you follow the persons head as they move (or you could just not risk following their head and aim for the chest, body, shoulders etc.). But, my ultimate recommendation is to buy a mouse and joy bad set, as in a mouse that you use with a PC. This might sounds ridiculous but, it's actually so much easier once you get past the early stages of using it which is very hard but, once you have got good with it, you'll find that aiming on to enemies bodies (or heads) is much easier as a mouse has no movement dead zone. I played for a while with a mouse but, I don't have trouble using controllers which are more comfortable to use!