Isn't Perceptol D23 with "something" added, I believe sodium chloride?
Sort of. Microdol is essentially disclosed in
US2466432A, Microdol-X seems to have adjusted buffering and added Chlororesorcinol as an anti-dichroic stain agent. Perceptol is highly likely to be very similar - and anti-dichroic stain agents are largely incorporated into emulsions today.
Just now I came to know that an older version of Ilfosol used the formula in the patent discussed
here.
And it's worth making a clear note that, contextually speaking, Haist and others by the mid-1950s onwards seem to have been discovering that HQMS, or de-facto/ in-situ HQMS, could/ did do the same job as glycin, but better. There's at least one fairly easily found defensive patent which hints at this. Ilford were also heavily involved in basic research to the same ends, especially in exploiting the properties of phenidones - that they all gravitated towards PQ formulae should tell you a lot - if Glycin was genuinely better, it would have been used. The transitional forms are interesting in terms of understanding why certain routes were likely not pursued, but should not be used to obscure/ obfuscate eventual research outcomes. Under the more rigorous methodologies/ techniques/ equipment of the 50s-70s, Glycin seems to have ended up as a bit of a dead end.