So I bought this EZ Share SD Adapter too, very cheap on eBay so I thought why not let's give it try!
For me it was easy to setup, I had an old 16GB micro SD card so I used that, first just formatted it to FAT and put it into the EZ Share adapter, then copied the exploit files to it (note I didn't copy any games to it)
Then turn on WiiU, go into internet settings and point it to the EZ Share hotspot. With a test you can see the WiiU connects to the EZ Share hotspot fine but fails to connect to the Internet - this is success of course because we don't want to connect to the Internet (no more updates, yay!)
Next just go to the browser as normal and go to
http://ezshare.card/index.html (the html file was the one in the definitive package) and you can load the exploit as normal.
For me I had the EZ Share SD device plugged into my computer the first time I tested it and kept my game SD card in the WiiU at all times and it worked well. In fact the EZ Share SD adapter just needs power to work so you can plug it into anything with a SD slot (TV, camera, phone,computer,etc) I even tested it in a USB adapter plugged into the WiiU USB port and it worked (see pic, note that it's not actually reading the card through USB here, just using the USB to power the SD card to send out the WiFi signal)
Overall this is a perfect solution for me, keeping my WiiU off the grid with an easy to use portable exploit solution that works anywhere my WiiU is.