Well folks I have to sadly say the drawings have been lost to the wind and being 20 years ago when I did these, my memory is faded a bit.
That being said, I figured this stuff on the fly and you can do it as well.
Step one is to get the foam head from a craft shop and enlarge the size by either wrapping it with a towel or laying the towels over it to better size it to you head.
Place the critters fur on the foam head FUR SIDE DOWN and the pinch up the areas necessary to form it to the head. These "pleats" can then be held with clothes pins or spring clips.
Once the "inverted" fur is fitted to your liking, mark the lower edges of the pleats on both sides, leaving room for the stitching. A little extra can't hurt, you can always trim it off. When the fur is laid out flat, these pleats will be triangular shaped.
Cut out the excess and then starting at the "V", use a whip stitch to sew it out to the edge.
With a little effort and fore thought, this process will not be complicated.
Hope this helps.
Jim