Warbird Information Exchange

Anyone run across definitive information on Aircraft Project Numbers assigned to A/C going overseas ?
By this I mean actual directives explaining their usage, meaning, etc.
Lots of educated guesses, some probably correct, but I would like to get some first-hand information, either from the source, or from a well sourced book.

As most probably know, these numbers were stenciled in the data block section of aircraft assigned to go overseas, although you can find pics of A/C, especially B-17's, with a Project Number stenciled on the nose section.

What section of ATC assigned the numbers ?

When were they assigned and applied ? Production-line, at Mod Centers, at staging fields just before crews picked them up to fly overseas ? I've heard all three of these from different sources.

Do the numbers have a code , such as " Project No. 92XXX-R mean this batch of A/C are to go to ETO/England ... or to certain Wings/Groups, etc ? I've heard guesses that different Theaters, Depots, Wings, Group destinations, etc, were coded by the numbers.
One unverified answer is that original Groups sent overseas had a Project Number assigned, and then A/C sent as replacements for combat/operational losses had the same PN with the " R " suffix.
Then again, I've heard a Theater or numbered Air Force would make a request for a certain number of A/C to replace losses, and when approved, that number of A/C being assembled or undergoing mods were assigned a Project Number to fill that request. What is the true story ?

Were different type aircraft assigned the same Project Number ? By that I mean, if say the 8th AF. or ETO, sent a request for 45 B-17's, 50 B-24's, 30 P-51's to replace losses for a certain time period, would all these various type A/C be assigned the same Project Number, seeing as they were all going to the 8th AF, or ETO, or Depot in England, or were differing types assigned different numbers ?

Does the " R " suffix denote replacement aircraft ? Other suffixes ?

Like I said, lots of questions come up, and lots of unverified answers, so I'd like to find out officially the word on these.

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SHAEF1944
American Veterans Museum