Well shot this weekend in terrible lighting minimum was 10,000 iso on D850, jpeg small fine*. Images came out very well. Still amending STD profile a little more, will test some more this weekend. AF was my issue this event. The AF was pulling off the athletes in 3-4 out of 10 frames. I tried going off spot to 9 point to group and back to spot. Seemed to be the location of lights near the head of the athletes, However i fixed that by switching back to Back button focus, hitting focus on the lower part of the action, when the athlete went into burst mode, i just hit shutter without refocusing, after that no AF issues. i dont get this on the D5, only the D850. Other than that the D850 did sooo well i was a very happy man. Great purchase, most important thing the client was very happy with the images.
On a side note: i was always very OCD about shooting in RAW, being Hi-Res why go lower res you got a D850, Low ISO, perfect settings and what this bad venue season has shown me is, you shoot the conditions you have and be happy if the client is. I would never have thought of shooting small jpeg before as being ok, but when the feedback is Drop the size, Drop the size again, i did worry until they said "perfect thanks, images spot on" i realised it really doesnt matter as much as getting the image does.