I'm sure you'll find both cameras will work just fine. You know how much I love that area. Your images will be spectacular how could they not be. Go have fun taking pictures.
Kevin
Thanks Kevin, so far both camera worked fine on the first afternoon (no surprise, of course). Attached one shot during the 5 minutes it took the sun to get out from the cloud layer and down below the mountains. This was with the D810 at ISO 64, 1/320s, f/8, 70mm using the Nikon 70-200 f/4 VR (lighter than the Sony FE 70-200 f/4
. Metering highlight weighted with +1EV adjustment. Post processed in Lightroom exposure +1.9, shadows +100, highlights -100, whites 0, blacks -31 and a few more things. It was shot a Passo Giau near the hotel I use outside of Cortina. It's also near this lovely church you loved so much.