Just tested VGpu mod myself. It works. I used 1Kohm vr.

Measure resistance between wires soldered on pcb. When you go below 47 ohm you will see that voltage raise. I tested 44.8 ohm and it gives 1.275V. Now my core can go over 670MHz, which was barrier before.

More voltage and results later

I think 1.3V-1.35V is more than enough with aircooling. With 1.275V idle is 58 c and load 77 c