I don't want to get into a whole "thing" here, but just to give an example, regarding his divided metol-sulfite formula (which is essentially Dalzell's modification of Stoeckler's), Thornton's comments about the alkali in bath B are flawed. To be fair, it isn't just Thornton. In general the descriptions and directions for divided development (where bath A is a developer), are somewhat flawed.
All I'm saying is be careful when you read technical books written by photographers, particularly when it comes to chemistry and sensitometry. The science is often incorrect and no evidence is presented. And when someone claims to be tweaking a scientifically balanced commercial formula such as Perceptol, have a healthy scepticism.
There's a lot of bad information out there - in books too.
Then again, if Thornton's formulas give you results you like, that's all that matters. My point here was not to worry too much about a Thornton version of Perceptol. That type of developer has been done, redone, and re-redone by Kodak and Ilford already.