You need to be just behind the tanker, like you see in videos. I use the light system in 135 just for approach, then only by eye (don’t follow the boom when you are close, follow the tanker).
Another thing is ED change the default view in VR for the A-10, moved back in the seat, that I found worst for refueling (and HUD visibility by the way), and I move the view forward, with Ctrl+Shift+Num pad keys, if I remember well.
Anyway, refueling is a long learning process, need patience and a good throttle control. Good luck!