By default emulationstation loads wbfs or iso for wii games. Although some games are hit and miss, this is how to make wiiware roms work on PC hardware.
obtain wiiware wads, copy these to the same folder as the wii roms.
Next from recalbox select nintendo wii, load one of your normal wii games either iso or wbfs, using the hot keys select and right trigger (might be different on other setups) you will exit the game and reach the emulator frontend for dolphin, from here you can go to settings and set a path for your virtual nand, you can also set the path for your wii games to make the next part easier.
you'll need a keyboard attached and mouse for ease, but right click on the wad file that appears in the games list and click install, might not seem as if anything has happened but the wads are really small and install quick. Test the game by double clicking on the rom, if it loads you are good to go, install and test a few more, bit hit and miss with them.
once happy exit the emulator
using an ftp client like filezilla locate es_systems.cfg and add .wad extension in the wii dolphin emulator section.
however you may have to make the partition writable as it might say read-only, in this case i use winSCP and the command mount -o remount,rw / i then reload filezilla and edit the file, there are better ways to do that.
now when you load recalbox in wii your wads will appear. if they are installed correctly they will load like any other wii game. strangely sonic episode 4 doesn't need installing but the rest do.
hope this is of help to some people out there, most probably been covered but hey few more wii games can't be bad :)