I tried in the thread I linked above.
A Simple Instrument Track (aka SIT) is a combination of a MIDI track and an Audio track. Some features are removed and the routing between the MIDI part and the audio part is done automatically, hence a simplified track for soft synths.
If you do not elect to use a SIT then the other track types are important.
MIDI Source is a MIDI track. Every soft synth must have at least one MIDI track and one audio track. So if you are inserting a new sythn and do not have an existing MIDI track for it, check this box (or use a SIT).
Synth Track Folder - places the tracks created by the Insert Soft Synth Options dialog into a folder. I usually do this when I am not using a SIT, to keep the MIDI and audio tracks for a synth together in a folder.
If you select a MIDI source, you will also need to select one of the audio output options.
For a synth with 1 MIDI track and 1 audio track, I will select either
a SIT or
MIDI Source, Synth Track Folder and First Synth Audio Output.
These two options should handle most of your synth insert needs. The other important option is "Enable MIDI Output." For now, you probably want to also turn it off. Synths that a capable of sending MIDI will do so, if this option is checked and it is always enabled by default. It can cause some unwanted data showing up on tracks if you are not careful. So for now, turn it off.
Brandon2000
The reason i ask is that it may be easier if i am just using two or three midi sounds, to actually have an instrument on its own track complete with its own TTS - is that a possibility?
Yes, multiple instances of TTS-1 may simplify you setup. Nothing wrong with it, the synth does not take much in the way of CPU or memory.