Brunner

Assuming that you're using the Data Editor software. Instructions here has accompanying screenshots, in respective order. This is how I set, say Slider1, for volume of multiple zones.
1. On the Stage Setting tab/Zone sub-tab of the Parameter Edit screen, enable Slider1 for all the zones that you want to set the volume control for. See Capture01.png
2. On the Stage Setting tab/Common sub-tab of the Parameter Edit screen, set the Target1 to Volume. See Capture02.prg
To set up individual Slider per zone:
1. Set all Target to Volume for Sliders 1 - 4. Set Min = 0 and Max = 127. See Capture04.png
2. In the Stage Settings, enable Slider1 for Zone1 and disable Sliders 2-4. Enable Slider2 for Zone 2 and disable Sliders 1, 3 & 4. So on.
3. Optional: In Stage Settings, Set ALL four zones' volume to 0 so you can flush Sliders1-4 all the way down at the after selecting the Stage Setting..
There is one thing that I would like to highlight - which I think is applicable to all Slider setup. In the 3rd screenshot, Capture03.png, is the Mixer tab which I highlighted the Level (volume) of Zones 1, 2, & 4 which uses Slider1. The default level is 40 in this case. In Capture02.prg, I highlighted the Min and Max values - where the Min is 20.
What this does is that if I set ALL my sliders to lowest (all the way down), the Initial volume of Zones 1, 2 & 3 is 40 when I pick the Stage Setting. And my Slider1 will be at 20. If I just nudge Slider1 up a bit, the value will probably be around 25-30 and this will have an effect of like a "bounce" or "skip" of the volume - in this case from 40 to 25. It's kinda annoying if you're already playing and you adjust it midway through the song. To work around this, set your Slider1 up to 40 or around it before you start playing - then sliding it Up or Down will have the desired effect while playing.
Hope this helps.

Finally bought a new PX-5S last week after watching videos of it online over and over. I'd say that I am a very satisfied with my purchase - kudos to Casio for bringing such a versatile stage piano and providing the Data Editor software.
I use the PX-5S at a small worship group and it is our main instrument. What I've always wanted was to have the Grand Piano as my main tone and be able to blend in Strings without having to press on a button or even move a slider - I need both hands on the keys .
I get to work right away and used MikeM's stage setting PnoStrLayer as my basis. I ended up with the following settings:
Z1 - Ice Castles (default zone OFF)
Z2 - ConcertStrgs (default zone OFF)
Z3 - GrPnoConcert (default zone ON)
Z4 - Warm Pad (default zone ON)
I use Pedal2 for Zone On/Off (Momentary) + Target2: Cutoff. I enabled Pedal2 only for Z1 and Z2. This setting allows me to blend in and fade out Z1 & Z2 which accomplishes what I needed.
Additioally, Z4 provides for an extra Wah or Choir sound at velocity 80. Slider 1 is set to volume for Z1, Z2 & Z4 to allow changing as necessary.
This is my first try at this and I hope that some of you may find it useful.