How to: Giga & keyswitches/articulations triggering?

[Sotorin3]

Do you guys have any advice how to approach the use of different articulations and patches in GigaStudio?
The Overdrive guitar library has everything I'd ever need to replicate riffs, power cords, leads etc.
Now, how the hell do you go about triggering all the articulations and patches (i.e. instruments)?
For example; 'long notes' instrument is loaded into channel 1, 'muted notes' into channel 2, 'slides/fx' into channel 3, etc. Now how would I program, say, an open or power chord for one measure, palm muted chord for half a measure followed by a slide to another note? Each instrument has different articulations, which I could program via MIDI but what about the ones on different channels. Will the long note be muted when when I swich to diffent channel (from 'long notes' to 'muted')?
Giga manual also said something about the ability to layer sounds. Would that be something I should take a closer look at too?