I have an Impulse 61, but I think I can answer some of your questions.
Automap works well with VST effects and instruments.
Automap works reasonably well with the mixer.
- On the Impulse, the sliders are dedicated to faders and the knobs can be set to control pan, sends, etc.
- Automap does not control the bus channels
- Automap does not control the Pro Channel
I think that the SL MkII has a bit more flexibility, but I do not think that it will allow you to control either the bus or the prochannel
If I really want a knob on a prochannel, I will put the Impulse into MIDI mode and have it control things via an ACT controller. This is a somewhat limited way to work, but suffices for those times that I want knobs on the PC.
Hope that helps.