Virus Indigo TDM Questions

[fm_xtk]

Bit of a blast from the past. I have been playing around with Indigo TDM and am wondering about a few things:

1. I can only seem to load 8 instances of the Indigo and a further 8 of Indigo V40 plug-in. Together they max out 1 DSP chip each. When I try to open another instance I get a DSP error (no DSP available). I was under the impression I could load up as many instances as I had DSP chips available?
   
   
2. All the instances seem to be linked together but I don't understand how. The manual is no help whatsoever. If I understand it correctly every instance should give me 20 (40/V40) voices of polyphony. When I set one instance to unison 16 the other ones go silent.
   
   
3. This makes me think that the plug-in behaves like a multi-timbral desktop synth (I know it is the same DSP as the original hardware) where you can spread 20 notes over 8 sounds?
   
   
4. The thing sounds pretty crusty and I am playing around to see if there is anything in it - in a sort of 2006 retro-style. Some of the pad sounds are half decent and I think the FX/drum sounds could be useful.
   
   How would I go about creating a drum kit with 8 different sounds, playable from one controller?

I realise that hardly anybody will be using this plug-in in this day and age. Like I said, it's for curiosity's sake and I appreciate any help!