I've cut a few F/F tracks for myself. It's super easy with a box cutter or razor saw. Plarail track plastic (polyurethane, I assume) is soft and easy to cut. I use curves since I have more than I need.
Making a M/M adaptor is more difficult, but I made a couple of temporary plugs to join two Female ends with a piece of EVA foam cut into a double wedge.
Making a M/M adaptor is more difficult, but I made a couple of temporary plugs to join two Female ends with a piece of EVA foam cut into a double wedge.