What i have found, with my SL MK3... is it makes sense to map the first 5 Faders.
Fader 1 Fader 2 Fader 3 Fader 4 Fader 5
Part Brightness Timber Time Movement
Volume CC18 CC19 CC16 CC17
Doesnt really matter for channel volume (I am using 41), but the others - are fairly consistent with the SLMKIII and Arturia's defaults... so I am using them. Anyway - I ended up hosting my Arturia synths into a Mainstage concert and using these CC messages. I keep every Arturia soft synth mapped to these CCs and positions on the SL MKIII. What I found that works.. is setting the first SL MKIII Parts (1-4) to hardware synths / external effects, and Parts 5-8 for a Mainstage Concert mapped as above. It's consistent across all songs, and makes using the SL MKIII as a master controller- way cool. Am using the faders above, along with aftertouch (CC:1 / Modulation) and the wheels for live play. I have a few other consistently mapped Rotary Control / Buttons for Previous / Next Patch, Favorites, and Previous/Next Song. I think there may be others... but the key (for me) has been setting up consistent Rotary, Faders, Buttons across Concerts, Songs, Patches, Controls. The SL MKIII is a great controller, after you figure out how you're going to use it - and how to map things..
Joe