Layering Poly-Foam

[Namivyn]

Hey folks 

I recently ordered and received some poly-foam for my first wolf quadsuit, but I wasn't expecting the layering type. My friend said I could layer the head and padding, but it'll be a lot tougher than carving the shape. I bought some thicker poly-fil for the head so I can create a sphere in order to include the muzzle,eyes,ears,etc. It's not ultra thick, but it's how big it would be compared to making the other foam thicker.

 If it's allowed to be asked, should poly-foam be transformed into a sphere for the start of the head via layering a lot or just find some thick foam to carve?