Hi tombax
It's an interesting question, to me too.
You see, I'm totally new to this world of computer music, so I'm trying to learn things one at the time.
Anyway, after a primal phase of over-reverberating everything (

), I'm now confortable with "dark piano hall" preset on the main insert. I tweakened it a little setting the mix to a 40% level.
This makes Notion Symphonic to sound acceptable through my tiny stereo deck and headphones.
At the moment.
But there's more room for juggling with buses and sends and inserts and...
A lot of very experienced people walks on this forum, I'm sure they will give you many other good advices on this matter.
Best regards