Try your local sign shop. If they cut vinyl lettering, you can get them to cut you a painting stencil. Then you can paint your white ltters on.

There is both clear and white decal paper. One tip if you are using white paper. Print the decal then cut it as closely as you need to THEN shoot the acrylic clear on. Often what happens is, if you shoot the clear on the whole sheet then cut, it leaves a path for contaminant to get in around the cut edge. This can be a real pain and cause bleed and such when you go to wet them and put them on the plane. Can also allow clear dope to seep in and cause some crinkling around the edges. Shooting the acrylic clear on after the decal is cut remedies a lot of this as it seal the edges pretty well.

Mark,

We fly out on Sunday for a week throwing rocks at the equator. I plan to see how much of nothing it's possible to do in a week.

I've never painted white over maroon, but know it doesn't work well over regular red. Primer first, then white. The best way would be to butt the colors, or paint the white first, but it sounds like those options are long past. I don't think most (thin) white vinyl would cover maroon, either, but thick stuff should. Maybe.  Steve