Little research has been done on these units. Confederate units were paid by the Central government whereas most of the units were paid by their respective state. You will find men from various states and many men who were formerly in the U.S. Army as officers as well as partisan ranger units which were consolidated to make up the various Cavalry Units.
All "regular" units and the vast majority of officers actually served in the "Provisional Army of the Confederate States" (PACS) and not the "Army of the Confederate States of America" (ACSA). Only a handful of high ranking officers were appointed to the ACSA to ensure that they would always outrank all militia, state, and PACS officers.