I think the white on white will get lost and the black on white may be too much of a contrast. You may want to look at a light gray to allow the letters to be seen, but not overwhelming. Subtle, that would be my course...
Good luck,
Jonathan
PS post pics of what you decide.... also you may want to try photoshop to get some direct feedback before you paint.
Good luck,
Jonathan
PS post pics of what you decide.... also you may want to try photoshop to get some direct feedback before you paint.



...that probably wouldn't look too bad at all 