How much would a b18 head need milled to achieve 11:1?

trying to achieve 11:1-11.8:1 Compression Ratio without changing pistons, how much %26amp; with what head gasket do i need to go from 9.2:1 to 11:1-11.8:1 CR in a B18A DOHC NON vtec?How much would a b18 head need milled to achieve 11:1?For that much of an increase, you will need to have the head milled.