G string probs

Hi everyone, just a small question regarding my Luke 2. Im finding it really hard to keep it in tune.
I have the trem raising a tone on the g string and I had a Tremel-no installed but have since removed it hoping to narrow out the probs thinking that was the culprit, I tried decking the bridge but in doing so the g always come back sharp after a dive (and flat when bending, but a quick dive on the arm brings it near into tune again?)
When the trem was floating the strings never came back in pitch (always lower)
I have tried everything humanly possible, big bends nut sauce, taking a very fine sandpaper to the g string nut slot, at my wits end here at the mo..
Any advice?