To play N64 with overclock all you need to do is
Install a Wii64 Forwarder
Copy the latest Wii64 app (
https://github.com/FIX94/Wii64/releases) to to the SD card like you would normally. (to SD/apps/Wii64)
Copy the Sign_C2W_Patcher.elf (
https://github.com/FIX94/sign_c2w_patcher/releases) to sd/WiiU/apps then Boot it from the HBL (this will reboot to the WiiU Menu)
Then boot the Installed Wii64 Forwarder
You should now have overclocked N64 Games
If you feel like donating donate to
@FIX94 he's the guy who made all this possible