Nah, no nerd here, just a pisshead with a pc as well.
I recall when I did the WASM plates i had the same problem.
But what you can do is don't worry if the width or height is out. Get the closest font. Place each letter individually so that you get the spacing ratio correct. Save the picture, and the resize the height and width accordingly.
It does take a bit of stuffing around. If you wanted to be a real nerd you could us the result to make your own font.
When I get back to perth (10days) I'll have a look at my stuff and see what I used to make the demo plates.
