Please remember that it is not sufficient to simply use Wiimm's DNS server when you want to see your favorite game being worked on. It is very important to capture network dumps on your own and to write down what you did in the game and when you did it - or even better capture the video along with the network traffic. Without any information on what has been done in game it is nearly useless to capture the network traffic...
Apart from that, make sure to do as many things as possible related to online gaming. Just to give a few examples, for MKWii this included connecting to WFC with one and two local players, also with completely new profiles, creating new friend codes, registering other friend codes by typing them in manually, registering new friend codes while inside a "room", joining friend's rooms, leaving them again, starting different types of games (versus, battle, coin), deleting friends from your list, connecting two or more Wiis for the same local network to WFC, starting regional games and global games, closing a room while other players are connected, connecting to a game by using your friend list and joining one of your friends, ...
As you can see, there are so many possible actions inside the WFC and without capturing and documentating everything, creating a fully functional server is not only a pain, but nearly not possible.