Unfortunately you cannot increase the number of channel slots on the menu
You may want to do one of 2 things
1) get USB Loader GX working (it has a GUI that mimics the Wii channels yet has no limit to the channel slots)
2) look into EmuNAND. Here's the SNEEK/UNEEK Guide I used.
Edit: just a heads up, your Wii U ProCon will not work with you Wii...it's a Wii U only accessory.