Wiiware are different : if I understand you correctly, you tried to play the PAL version in NTSC (because the PAL version is presumably interlaced, or even 50 hz?)There is a WiiWare game that I tried to force to NTSC without success and it is Chronos Twins DX from the EU version. I activated all possible patching options but no luck.
I provided a tutorial to make a Wiiware game region free with ShowMiiWads when I released "Line Attack Heroes", but if you just do that to switch between PAL and NTSC you will (in my experience) end up with a choppy framerate.
What you need to do is use WwPack : the .bat file will provide you with several choices, including "patch video mode", and you will end up with a file named "Game (Europe) [Patched] [Loader] [RegionFree] [Video].wad".
I did that to a lot of NTSC games that either weren't released in Europe or were an inferior version, and they all play like a charm, so I guess you could easily do the opposite.
Good luck with that!