Here's a photo of the one I used. It fits over the number plate and is secured using an adhesive pad.
It needs to be at a prescribed height and you can get the dimensions online from the MSA website, just find the "Blue Book" and search for "timing strut".
If you're making one let me know and I'll send you a cardboard template as the drawing is eluding me. A tip is, not to make the strut too sturdy, because if you have a small indiscretion, it's better to sacrifice the strut rather than the body panel behind it.
Regards,
Clive,