IMHO the easiest way to work with a multi-timbral synth like that is to use separate MIDI tracks for each channel used in the synth. Helps me keep things visually aligned, and I can see at a glance which channel is assigned to which track. Make sure to set the track view mode to I/O, or ALL, so you will see the MIDI outputs for each track. You can minimize the tracks after making assignments to hide this I/O info, but it is helpful if you assign relevant track names to each MIDI track.
Try instead of inserting a simple instrument track, add the MIDI source, and the audio outputs, then add as many more MIDI tracks as you plan to use. If you do this often, setting up a track template can make this a snap in the future.