I wouldn't get into cutting the ports at all if I were you but I'd take a sandpaper bit to a dremel and smooth out all the ports. I know in cars when you start to cut the ports it's usually a good idea to have a gasket to match your porting too, and they never cut the botom of the ports, only the top and sides. If you just have a 200x, see if you can pick up another head, use the worse head of the two and do a do it yourself port job and put it on the bike and see how it fares. Those machines only have 2 ports, so it wont take long and wouldn't be hard or expensive. I'd try it maybe if you can afford another head and the time.
1986 ATC 250R(for sale), 1963 AceCraft boat w/40HP Evinrude, 1981 Arctic Cat El Tigre' 440 L/C, 1992 GMC Safari Van.