Getting a professional fitter to do this but buying the carpet myself. It's a T shaped area. Landing upstairs at the top of the T is gonna have to be 4 metre width. The steps are the vertical bit of the T, much narrower (1 metre). Carpet available in both widths. If I get a piece 4m wide and leave enough overlap to comfortably go over to the the bottom of the riser of the step that meets the landing, can I get away with doing the rest of the stairs in the narrow width? Otherwise, if I bought a 5 metre length of the 4m width roll, about half of it would go to waste! No bullnose on the steps if that matters.