Sharke,
8 buses for me will typically be:
1. Drums
2. Guitars (+ bass if desired)
3. Keys
4. Vocals
5. Room Verb
6. Plate Verb
7. Hall Verb
8. maybe Bass if not on 2.
Note 5/6/7 are max case but at least one bus would be a verb bus for sure.
I would bring tracks from SONAR somewhat EQ'd and compressed but not verb'd.
And of course I could still have an optional master bus "glue" reverb.
For me I've pretty much ruled out utility buses.
YMMV