There are basically two different ways of using Multi out VSTi's here.
One is with an instrument playing a midi part on it's track and putting out to multiple outputs. That way, the midi data (for instance drumpatterns) are on one track also holding the instrument, and the instrument puts out to output tracks. In the case of drums this is nice, because you don't want to edit your kicks-snares-hats all on different midi-parts on different channels. Let's call this a rhythmic template for now.
The other way is the same, but with multiple midi-channels feeding the VSTi. That way you can play the instrument on different midi-channels, each with different melodies on them, playing different patches on the VSTi. You can do that for instance with Sampletank or Sonik Synth. Those ROMplers can have different samplepacks on different midi-channels. So now you can use midi-in 1 in the template to play a piano melody, while midi-in 2 is playing a Hammond organ. That's more of a melodic template if you like.
So...... Basically if you include these two basic templates, you can cater for a variety of VSTi's, drumpattern based or melodic.
Just plug your VSTi of choice in the VSTi Track, tweak it's patch and channel settings and away you go, make music! On the 8Out-4in template the midi-channels are made not to show up in the mixer, since they have no function there. If you need more or less tracks, just delete/add to them and check their routing.
Many thanx to the excellent explanation of Talisman! Read his explanation here:
http://www.cockos.com/forum/showthread.php?t=8355
To Justin: if you like, you can include these templates in the next update. It will solve nearly every Multi VSTi issue of people I think...
greetzzzz!
PS: The one with 8out-8in has the midi channels all below their corresponding audio output track (alternating audio/midi channels). Found that you can re-arrange the midi tracks as you like, even putting them all in a folder of their own to get them out of the way. All midi tracks are invisible in the mixer.