Update: RESOLVED
Yeah, thanks, everyone. This has been solved.
I just needed to delete the old Luma3DS updater.
I was opening the old updater and getting confused by what it was telling me. -_-
Everything seems to be fine with the new Luma3DS updater. ^^"
UPDATE:
Got the first card: TS64GSDXC10U1
Formatted with this tool: http://www.ridgecrop.demon.co.uk/fat32format.htm
Took only a couple seconds or so.
Copied my old card to the new one, and everything seems to be functioning fine.
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(Wasn't sure if I should...