my friend has this problem.
she's on PAL wii, and playing NTSC games render in black and white (video cable's fault/old TV).
on usbloaderGX, Trying "force PAL60" and vidTV ON solved the problem for most games, but the better compatibility she got was using "auto patch + VidTV on".
autopatch is getting a better aspect ratio image (in one piece for example, auto is great and full screen while force pal60 render in 576i + little image).
So if you are on NTSC wii, you can try force NTSC + VidTV, or auto+VidTV, and see what is the best for you.