I've been working in the baptismal records of St. Augustine during the early part of the second Spanish period (Volume I, 1784-1792) in the transcriptions available at the St. Augustine Historical Society research library. It is much easier to use these transcriptions, at least from 1784 into the fall of 1788, because the entries during that period were made in Latin, and I do not read Latin. It was in 1788 that Bishop Cirilo de Barcelona made his visita (inspection tour) of St. Augustine and he decreed that henceforth entries should be made in Spanish. He cites errors and other unacceptable conditions in the records, and prescribes a form which is preserved in the baptismal record.
I have also just finished transcribing from the original the 1786 census of St. Augustine taken by Father Thomas Hassett, the priest at St. Augustine. It is not a complete census, as Hassett himself points out in his introductory comment. He purposefully left out the government officials and the troops stationed at the Castillo de San Marcos. Spanish censuses frequently left out military personnel. For one thing, they were probably considered transient, even though other records I have examined show many of them participating in the daily life of the town.
These documents, along with marriage records, form the basis for reconstructing the family structure of the town, and I am beginning to see patterns of relationship. Another aspect found in the baptismal records is the godparent relationship, which I've mentioned previously.
It is necessary to bear in mind that with these Spanish censuses, however, the one consistent aspect of them is their inconsistency. There were no prescribed formats and no preprinted forms. Not all entries have all the information. For example, it is traditional in Spanish records (as it is in French records) for a woman, married or not, to be recorded by her maiden name. This is a boon to family historians researching their female lines. Most of the entries in the census and baptism records have the women by their maiden names, but not all of them. Then, too, it is careless to assume that because the woman's surname is the same as her husband's, that it is not her maiden name. Non-first cousins could marry, and sometimes did. It is also possible that, even in a town as small as St. Augustine, you could have two unrelated individuals with the same surname.
More information is necessary in these events, and the marriage records are the best source for that.