There are two approaches:
1. Use WiiMode WiiU decrypted system menu file (after running ancast decrypter to get that file) and find similar lines of codes that you could see from the corresponding file of the Wii version. Then converting those found file offsets to memory offsets. However, the memory offset on WiiMode WiiU starts after 0x81330100 while on Wii starts at 0x8132FAE0. So if you are following SifJar tutorial, you need to use that number 0x81330100 for WiiMode WiiU to convert from the file offset to the memory offset instead of using the regular 0x8132FAE0.
2. Or you could directly use the memory dump of MEM1 when you are in system menu under SNEEK environment to search those corresponding similar lines of codes.
I also used the approach #2 to verify the approach #1.
Cheers.