I think emuNAND is what you should look at.
It's a way to install WADs to SD card
you don't need to install + move, it's installed on a copy of the Wii located on SD.
The console redirects its memory access to SD, and use the SD card as if it was its own internal memory, allowing you few GB of memory instead of 512MB.
There are two type of NAND redirection :
one done by the cIOS (if you use USBLoaders, you should already know about that), it's a "live" redirection. the game is redirected in real time. To use that mode and launch games, you need a loader.
The second one is done with Neek. It's reloading the console in a full redirected environment, the internal memory is NEVER accessed, and the console don't even know theres a redirection occuring. All the SD card is acting as the internal memory. to use this mode and launch game, you use the official Wii system menu. it's more natural.
You should read this guide I wrote if you are interesting :
https://gbatemp.net/posts/6592730
