I made a remote editor for the system functions of my reface CS. I was tired of the tedious procedure of switching off, press and hold a certain key, switch on again- and remember the right key or keys for the needed function. So I checked the documents and found that all those functions can be controlled via MIDI sysex. I started to make a MIDI Designer based controller layout. Now I can e.g. switch local control on and off, change the MIDI channel, set the looper metronome to either guide or click sound etc with a tap on my iPad. Unfortunately a few of the newer functions are not yet described in the data list, so I had to do some trial and error.
I also set up two buttons for what I need most often: to switch both local control and speakers on (when I play reface on its own) or off (when I play it through my DAW).
Finally I added a second page doubling the physical sliders for setting the sound, just to have access when the Reface is out of reach of my hands.
I shared my layout on their website, so if you use MIDI Designer, you can get it here: http://mididesigner.com/qa/5623/layout-remote-editor-for-yamaha-reface-cs