Lock grid to the viewer?

I shot a bowl spinning on a rotating black mirror with the camera on sticks.. Becuase the mirror was 4 feet square getting the bowl exactly centered wasn't possible so it has a slight movement as it rotates. To correct that I need to stabilize it manually as the rotation confuses the trackers. What I want is a back ground on V1 and the clip on V2 and then move the clip on V2 to keep the bowl centered in the viewer not in the clip..

If I put the grid on V2 it just moves with the clip so is useless. I can't put it on V1 as you can't add the grid to a generator. I created a transparent PNG and put it on V3 and added the grid to it but I can not get the grid to show. I am kind of pulling my hair out. Is there some way to get the grid to lock to the viewer rather than the clip? If no is there some way to get the grid to show up on a track other than V1?

Bonus question any thoughts on how to stabalize a rotating object automatically?

Thanks in advance

You can add the Grid effect to a Color Generator if you first convert the generator to a compound clip.

Thank you very much.