This post is probably for very few; forewarned.
Scalometry and the Pauline Epistles
This resource is unusual. Logos.com has a select number of resources that look at authorial 'usage patterns' ... Old Testament, and New. Spelling patterns, syntax, vocabulary, etc.
Scalometry, as the word suggests, looks at scale, and in this case, sentence and phrase length by presumed author. It was written about 20 years back; I'd say the technology has progressed considerably. But the patterns the resource demonstrates are quite interesting; he hypothesizes start-stop dictation sections to explain the patterns.
But unique to this resource, if you're interested is verse by verse comparisons of what are often viewed as later epistles ... Eph, Col, Pastorals, Hebrews, Petrines. It's quite eery, though he suggests a missionary group that worked off the same teachings (expressed slightly differently, but in greek, quite similar).
I'll still want to re-read the 'scalometry' idea; people do vary how they express themselves, relative to genre. But definitely I'll want to re-look the 'late' epistle patterns.