I’m inclined to mark the text’s internal divisions (suffrage, versiculum, responsum, and oratio) using the flexible <div> element; give comments on decoration using <decoNote type=”miniature”> and  <decoNote type=”initial”>;  and indicate rubrication using <rubric>.

Marking abbreviations will be tedious, and although it’s possible that this data could yield research results, it doesn’t stand out as significant. I would prefer to mark abbreviations in a simple and streamlined way—the option that looks best to me is “silent” expansion with <expan> without the further use of <abbr> or <choice>. This would not distinguish between different types of expansion or mark common abbreviation symbols, but it would still be searchable for anyone specifically interested in abbreviation practices.