In my opinion, the need of a chin tuck decreases when you learn to balance your skull on the weight-bearing part (the disks) of your spine, on the atlas. Tension on the neck and back tends to tilt the head backwards (while it collapses forward), so when you chin tuck it feels as if you counteract that. 

So if you learn to balance your head, the root of the problem is solved. I don't know for long you will need to do this exercise*, but it's okay as long as it helps achieve balance/alignment and you feel better.

*I personally move my head around, tilting, nodding, etc,  in conjunction with mewing,  until it feels balanced and free. But I can see how chin tuck can help achieving that as long as it is only used as an exercise and not as a fixed position.

Chin tuck is only an exercise, don't overdo it lol, but at all times there should be a 90 degree between your head and neck, basically tuck your chin in slightly