R., If I were you, I would go with John2000's method. That will give yopu more options later if you change the flooring and so on over time. There is one place that you will have a problem though. If your doors have the typical plywood door skins, they will be difficult to cut without the plywood being real splintery. Before you make the cut, score the top side that you are cutting with a utility knife just above the cut line. The score will stop the splinters from going up further.