I'll have the same results if I try to move the N number like you did. I'm actually going to paint over the old numbers in white and then mask them off when the top half of the fuselage is painted red so the numbers will be white. They might get a blue outline when it's done, don't know for sure.
Now that I have a more definite plan on the new trim scheme, there is less sanding to do and things are moving more quickly. One side is done, we'll cut the grass and edge a few trees today and then get back at it.