Multi-timbral Channel Mapping in Mainstage 3

Hi everyone,

Just dove into Mainstage 3 a couple of weeks ago. I have a Yamaha PSR S950 which has internal song arrangements. I want to treat MS as a 'sound module', triggering different MIDI layers in MS as opposed to the internal sound bank. My problem is the MIDI Channel assignments from the Yamaha, and the inability to make sense of those in MS.

They are CH 9-10: Drums, CH 11: Guitars, CH 12: Strings, etc. up to CH 16. The only way I've seen how to set up multitimbral instruments is to assign channels in the MIDI Input section. But with this method, it seems that a keyboard has to be setup in Layout Mode for every single layer/channel. There's got to be an easier way. Am I missing something? Also, would each element/channel coming out of the keyboard have to be within one patch or could I split them up into separate patches and play them simultaneously that way?

Would appreciate any feedback at all on this. Thanks very much!