Bro at how many lbs did you string your Nanoray 900 ? I am looking to buy Nanoray 900 too. I also have ZF-2 , which I will use for singles. I hope I am making the right decision, this being my first head light racket.
That was my old post back in 16, I was using 27lbs back then, now varies from 28-32lbs depending on string type. I would lower the tension on thinner gauge string (0.63 and below). The higher the tension, the harder the stringbed and need more energy to generate a powerful smash compare to lower tension. NR900 has a lot faster swing speed than VTFZ2, so you would need some time to adjust to the swing.
You still have the Nanoray 900 ? How do play with both NR900 and VZF-2 ? How did you adapt to both Head light and Head heavy racket ?
I like head heavy rackets better so i keep the VTFZ2 and parted way with NR900 3 years ago, now with Astrox 88 S/D.