Whew!! This is a tough one!!
Ok, here's what I would do.
1. Wet sand the whole area around the number outlines to get rid of as much of the edge as you can. Then, buff out the finish.
2. Carefully align each of the numbers over the correct locations . This should hide the previous outlines with the new numbers. Take your time with this.
3. Another option is to make a stencil using the new numbers. Then, after wet sanding , tape the stencil directly over the numbers location and paint the numbers on the car.
Either way, the final result will depend upon the amount of detail you pay to number location and placement of the vinyl numbers or the stencil.
