I’ve been using a 4’x6’ horse mat for stopping missed arrows when me and friends practice. It works great! The problem is that moving it around it’s very heavy. I recently saw a setup with a 3D of a deer standing in front of a sheet of “r-tech” 4’x8’. Has anyone tried this, and are you using more than one sheet?
If you’re referring to polystyrene insulation sheets I’m thinking it would take a lot of them to stop a hunting arrow. The 4’x6’ horse mats are actually a good idea but you’re right when you say they’re heavy. I hated moving those around. I’d bet they would stop an arrow though.