I tried that and is like set the video mode on force pal50 it only shows black and white screen. I tried the video deflicker option, didn't do anything and also the progressive patch option, this only gives black screen without audio.
I formatted my wii and reinstalled all my wad files, I updated nintendon't and usb loader gx. Nothing changes, the same result.
I also checked the nintendon't page where they have a compatibility list and my iso isn't compressed and it has the exact same md5 number that the page of their suggest. In that page says "Width must be set to default or else game shows no picture." I selected AUTO, didnt't work, I tried to set a specific number, didn't work, indeed didn't affect the width.
Finally, I tried to load the game from my sd and my usb, both have the same problem. My only guess is a TV issue, but I used to play MP1 and MP2 with this TV without problem, same cables, same Wii, all is the exact same.