[1] He was friends with, and a correspondent of, Richard Bentley, master of Trinity College, Cambridge, who assisted him in the production of a hasty edition of the works of Aristophanes.
[2] Thomas de Quincey was later to say that Bentley's contributions—including epistles on The Clouds and Plutus—were "mangled" by Küster and incompetent printers.
Several times, Küster came into professional conflict with Dutch classical scholar Jakob Gronovius.
In 1710, he made a reprint, or rather revision, of John Mill's Novum Testamentum Graecum (1707), with prolegomena and with collations of 12 more manuscripts.
He is mentioned by name in Alexander Pope's satirical Dunciad, in the company of other notable classicists of his day.