I've burnt through about 6 x 30m bulk loads of Neopan 1600 over half a dozen years . After some initial tests I standardised with D76 1+1 and the film rated at 800 ASA with extremely good results in inclement weather.
Also found it very good indoors, as Tony Egan has.
In bright sunlight, forget it, the contrast is so bad no matter how you develop or print it, it just doesn't come out looking good.
It works best for me with my 85 1.4 as I can see quite well with such a fast lens for focusing in dim light and yet still get very good printable negatives.
Mick.