Racing numbers in the 1950s and 1960s

[baclightning]

Ok, I know that people may find this a bit esoteric, but if anyone can help, I'd appreciate it. I came across a book from my childhood, Racing Cars of the World, published by Hippo Books, in 1962. It's in a 3" by 5" format, with entries for 64 then-current and historic single-seat racing cars, with one page of specifications and a full-page photo for each car. Looking at the photos of the cars, I was struck by the differences in the way the race numbers were applied. Some looked professionally done; others looked like they were applied by chimpanzees. Sometimes there was a bit of an overkill, as in Stirling Moss's car at a race in Italy in 1956*:



I know that in Formula One, etc., permanent racing numbers for the full season weren't introduced until the early 1970s. Before that date, each race organiser handed out individual numbers, meaning that even a famous driver such as Jim Clark could drive car #5 in one Grand Prix, then #3 in the next, and so on, as in these shots from 1967 (I love putting the driver's name on the car, too). A blank circle was often left for the number to be applied.





My questions are these:

How were the numbers applied? Painted by hand, painted with stencils, decals, stickers? If they were painted over for each race, wouldn't that get a bit heavy by the end of the season?

Who was responsible for applying the numbers? The race organisers or the teams? If the latter, did each team have someone with artistic ability assigned to apply the numbers at each event?

How were the numbers assigned? Order of entry? I know that Stirling Moss considered "7" his lucky number, and tried to race a car with the number "7", or a multiple of "7", such as "28", whenever he could. Could drivers request a specific number?

Why did it take so long for F1 to go with permanant numbers for a full season? I can see individual numbers in each race for the lower formulas, where entry was fluid, but in F1, it would seem logical to provide stable numbers for the major teams, and still have a few high numbers still available for "one-offs".

Anyone who was there, at the time, if you could fill me in, I'd appreciate it.

* Just to be clear, I grabbed the photos from the web, not from the book I mentioned.