Okay, while my 4.3U emulated NAND works great in SNEEK+DI, it doesn't work at all in UNEEK.
To get it to work, I had to install IOS70 and 4.2U using ShowMiiWads. Now, UNEEK and UNEEK+DI load up as expected.
However, when I try to launch anything, (a channel using just plain UNEEK, or a 'disc'...