Hi,
I would save money and buy a non Nikon...
I had a Tamron "G1" version at my D750 and later my D850.
Fine tuning with my D850 went quite well, but it was a compromise.
It was sharp at 24, 35 50 mm but not quite tack sharp at 70 mm.
If I tuned it that it was sharp at 70 mm, it wasn't at 24 and 35 mm.
I didn't have that problem with the D750.
A comparison with the Tamron "G1" lens and a Nikon 24-70 non VR resulted that the Nikon wasn't sharper, but it's AF was faster.
6 months ago I bought the Tamron G2 version.
With Tamrons docking station, I could fine tune this lens perfectly.
AF Fine tuning at 12 (!!) places in the lens.
At 4 focal lengths and at 3 object distances.
In a comparison with my friends Nikon 24-70 non VR lens and my new G2 version, my new Tammy was the winner...
Sharpness is perfect now and it's faster as the "G1" version of Tamron, I think at least as fast the Non VR Nikon if not faster.
The Tamron lenses are smaller as the Nikon versions.
The Nikon 24-70 lenses extends less as the Tamron 24-70 lenses.
I don't now how Sigma 24-70 lenses or Tokina 24-70 is in sharpness and speed.
Which is the best 24-70 to buy?
It's a personal thing, I think you can't go wrong.
Both Tammy's and Nikon's are very good (Sigma and Tokina maybe too...).
I hate to pay too much for something, I'm not a "pure" Nikon fan.
The Nikon VR cost more as twice as much as a Tamron G2 version...
My wife and I could go on a nice holiday for a week, for that price difference... What do you think my wife was saying...??
This was the psychological approach ...
Tell your wife, the Tamron lens cost about €1200,-, the Nikon version cost €2500,-...
After that, you say to her you don't know for sure which to buy...
She will be happy if you buy the Tamron and go both for a holiday to a nice warmer spot in winter time... :loyal: :encouragement:

(We went to Sevilla, Spain for a week...)
Plaza de Espagña, Sevilla.