Ah, commas are the tiny hinge points that let a sentence swing. In 18th‑century letters, a misplaced comma can turn a polite address into a terse command, and that shift drags the whole visual rhythm of the page—think of the line spacing and the way the ink spreads. For an exhibit, I’d map each comma as a separate annotation in the margin, noting its exact position; that way you preserve the original flow and keep any hidden conspiracies that the punctuation might be hinting at (1).

Got it, I’ll choose a light‑weight, narrow serif—just enough to match the period but muted in size, so the 18th‑century script stays front and center; that way the commas do the heavy lifting while the notes stay supportive, not distracting.