Brightness 50 and Contrast 6, Should give you a very pleasing brightness without compromising details.
At the above settings you will be able to clearly see all the black segments in the Black Test @
http://www.lagom.nl/lcd-test/black.php
And up to #253 on the White Test @
http://www.lagom.nl/lcd-test/white.php (255 is visible if you squint quite a bit!)
I found the luminance using 50:6 is 121cd/m2 so right on the money for recommended brightness for an LCD*
*You will most likely need to use the monitor daily for several weeks before it settles in, I found this to be the case on mine as the brightness/contrast adjustments never allowed for 120cd/m2 when I first got the monitor back but some time later it now does