I have not been able to translate this yet as this computer does not do "pdf".
I will figure out a way.
The book "The Roman Imperial Army" does give the locations of the legions in Briton, at least.
I do not think the romans counted on having a minimum of 4 Legions in Britain ad infinitum-as many as were kept on the Rhine Limes, but it speaks well of their respect of the Britons.
Also, I think, augustcu thought to keep only 28 legiones in the 'Army of the Principiate"--but I think, and hugh will correct me, that the losses in Trans Rhine Germany may he upped this to 30.
A kink ( or salient) in the Rhine Frontier known as the "Agri Decumantes" at the time when Imperial ambitions settled on this frontier may have made the frontier less defensible than thought.
"All Enlightenment Gratefully Accepted"