I can't say I've come across a specific book on SCW organisation and tactics, certainly not in English, and some of the information which is out there is based on urban myth (like the two company organisation for the Regulares).
There are a number of wargamers guides which are useful references, two which spring to mind are 'La Ultima Cruzada' by Bob Cordery and the 'Rompan El Fuego' Rapid Fire supplement.
There isn't a general tactical history of all the various battles either, but there are specific books on individual battles, e.g. the Osprey on the Ebro Campaign is quite good despite some dreadful typos.
Some details can be gleaned from the more general histories, I still find Hugh Thomas's book the most useful in this regard. Anthony Bevors latest re-write of his SCW book is also very good, but like all general histories, maddeningly vague at times. Avoid his earlier one.
If you head over the the SCW yahoogroup, there are lots of useful pointers and discussions there.