I had a new sliding glass door installed, and I want to install molding around it. I'm buying 3 inch fluted molding and rosettes for the corners (no mitering needed). First, I have to stuff the rough opening with insulation. and then I can install my molding. Should I use an adhesive on the back of the molding? Do I need to pre-drill the holes in the rosettes or other molding? Any other tips would be appreciated.