I ordered one from Aliexpress, it arrived today.
It works great, exactly as you would expect. Two knobs, one adjusts horizontal position, the other vertical.
Thanks so much for posting about this! Mine arrived and it works great. I have an older PVM that doesn’t have an on screen display so I’d have to open the case to adjust the picture. With this my Volfied PCB can be centered perfectly! Woooooo!