In the USB Loader GX GitHub, they give us two configurations.
One which is the most optimal for Wii's:
Slot 249 base 56
Slot 250 base 57
Slot 251 base 38
And another which improves compatibility:
Slot 248 base 38 (Wii only)
Slot 249 base 56
Slot 250 base 57
Slot 251 base 58
Would it be safe to use the cIOS configuration that improves compatibility? That's all I'd like to know, thank you for reading.