USBLoaderGX is used the same way on Wii and vWii.
The only differences on vWii are :
- You can't install different cIOS version (only d2x v10 and v10-alt are available, no Hermes or old cIOSes). If you follow vWii softmod guide you will have the correct cIOSes.
- You need HDD with external power sources, or use an USB Y-cable to power the drive using both USB ports. (some drives require more power than the WiiU can provide on a single USB port. Some drives works, just try.)
If you want a tutorial to hack/Softmod your vWii, you can look at the two stikied topics in this forum's section.