Sg(Stanley Gibbons) Booklet Numbering Method

Is there some summary of the logic on how SG numbers booklets?

We have prefixes of Dx, Fx, PM, MB, etc. I realize some are specific types. The Concise does not summarize them.

Of course, their Machin numbers are not as consistent as it could be too.

D, not DX are stitched booklets, DN 10p, DH 25p, DQ 30p, DP 35p, etc.
DX Prestige Booklets,
F folded booklets: FA 10p, FB 50p, FC 65p, ..., FH £1
G barcoce - also windows - booklets same principle
H also, but with "no value indicators"
J also, but Penny Black Anniversary
KX also, but Greetings stamps
LX also, but Christmas
the P was used for self-adhesive booklets

You may notice there is some correlation with the first issue of the type of booklet.

Thanks. This helps.