As glossy as that fairing looked, I blocked it down with 1200 wet and dry (only use it wet) and grey scotched it so I can paint white number backgrounds.
Minimum sizes for these on the sides is 260mm wide by 220mm height. There's a really easy way to mark an oval shape out and to save me trying to explain, take a look at this cheesy link. https://m.youtube.com/watch?v=hp7AxUVX714
Drawing it out slightly oversize to allow for the width of fine line tape then gives a good template to help mark it out on the fairing. Once I have it positioned where I need it, I fold the paper over on the rear edges of the fairing and the crease helps as a reference point when lining up the other side. I didn't have any large paper, other than this gift wrap stuff, which also has grids on the back, but this helps to make sure you get it level. The right hand side of my fairing would make it really awkward to stick vinyl on, and this will just look so much nicer.
I'll try to learn how to insert pictures in between text, but the quickest way of masking a fairing up for this is use a plastic bin liner and cut out the area you need to paint. You get no paint where it shouldn't be. I dropped on 3 coats of solvent basecoat and after it dried, which Doesn't take very long, gave it a light sand with 1500 grit wet paper to lose any edge.
I'll take a few more pictures tomorrow, but I'll be lacquering the whole thing again and you won't be able to feel any edge or step in paint from the number background. I took pictures on my iPad, which I hate, so if they're upside down, I'll fix them on my laptop!