Got to work carving the head and upper body.

I started with polyethylene pipe insulation.  The poly insulation is about 1/8th the cost, but nothing sticks to it very well, it's very stiff, and it has a much larger open-cell structure.   The wire brush trick to make it look like wood also requires heating it afterwords to get it to look right.  I didn't like the results so I scrapped it all and started over with neoprene.

Also ended up making panels from the softer neoprene pipe insulation for the head.

Gluing it to the spandex gave it a stable base so it didn't immediately tear.  This allowed me to cut/sand it to shape nearly down to the fabric which gave the resulting mask really good flexibility.

It seems I originally forgot to post the following video, so here it is.