I am in the process of installing my NC30. Hearth is built and stove is setting on it. I put the hole in the wall today. Boy does that make me nervous cutting a hole in a perfectly good wall.Anyways in installing Supervent pipe bought at the local Menards.My delima is, on the install instructions it list , universal shielding insulation as an option to use between the thimble and the wall studs. It says optional and the left over space is minimal. I have insulation that was in the wall when the house was built.. Will this be alright in the cavaty, The 2 inch clearance would still be intact..Is your thru the wall install insulated in this area or not?