How would I select the nvidia (with nouveau drive), since I assume it would be more efficient.
What makes you think, nouveau would be more efficient than nvidia blob?
And i would oracle, nouveau would not support your card really, but without an
update-pciids
inxi -G
it's hard to say, if nouveau would support that card initial.
For me bumblebee is a crappy solution, but sadly it's the only available in debian, since the better tool nvidia-prime isn't packaged in debian.
With nouveau you could use dri offloading to activate the nvidia gpu for the choosen application.
All over all i would never buy such optimus hardware.