I do not understand how to set up for different thickness boards. I want to drill pocket holes in an 1 1/2" thick board and attach it to a 1/2" thick board. Where do I set the stop on the drill bit and where do I set the guide? Quick start manual refers settings to thickness of your work piece but which work piece? They are different thicknesses. Also which screw do I use so as to not go through the 1/2" plywood?