Sewing the back of the head

I've made 2 fursuits so far and each time the back of the head is something i've really struggled with.

Either it ends up too tight and the whole thing has to be redone, or it ends up too loose with bunching material which looks awful.

Is there some kind of technique i'm missing? - since even the most amateur of suitmakers seem to be able to get this, yet I just.. Can't seem to perfect it.

Also, it is more common practice to sew the back of the head to the rest of the face material, or to simply glue it down to the foam/ resin, and hope it has a strong hold?

Thanks!