Fab round-up Key Fumbler.
There's also a volume slider for each layer in the layer panel, so if you like the instruments as they are, you don't need to alter them, just up or down each volume to adjust.
There is also a per layer 'M' and 'S' (mute and solo) to help with listening/deciding as you go.
I find much of the usefulness of using layers comes by using quite different sounding layers but complimentary, rather than each having equal presence or force/power.
The way I like to use layers most, is by using layers 2 and 3 for 'supporting sounds', quiet often, like reverb, or 'distant' FX if wanting something more unique.
Def. don't forget Key Fumbler's #5 point.. width/stereo.. you can for example, edit layer 2 preset 'mics' so they lean to the left.. edit layer 3 mics so they lean to the right.. create your own 'wider' vistas and FX.
I know you'll have much fun WeightedKeys!
Pianoteq Studio Bundle (Pro plus all instruments) - Kawai MP11 digital piano - Yamaha HS8 monitors