It's fine to update if you have it then, 11.1 payloads are out now so pretty much everything (most power users use) are useable again (NTR needs some extra steps done in order to use it in 11.1)
For creating an emuNAND in Luma, you need to just simply use Emunand9 to create it.
1) Make a backup of your sysNAND and copy ALL the files from your SDCARD into a folder on your desktop. (Always be safe then sorry)
2) Put your SDCARD back into your 3DS and launch Emunand9 (You should have this as a payload since you did the guide: I have mine assigned to launch upon pressing Y)
3) Go to "SD Format Options..." and choose the "Format SD (Emunand default)"
4) Wait for it to do it's thing and after completion, shut it down and copy all your files from step 1 back into your SDCARD
5) Power up your 3DS holding select and make sure to turn "Autoboot sysNAND" off and turn on "Use second emuNAND as default"
6) Reboot and success! You now have a emuNAND! (Reset it if you want: I prefer it)