I don't know of any other uses of "at" for "out" in that day.
In his 1833 revision of the KJV, Noah Webster wondered how an error remained uncorrected in the KJV for more than two centuries in Matthew 23:24 (misprint "strain at a gnat" for correct "strain out"). The Cambridge History of the Bible noted that "strain at" (Matt. 23:24) "was almost certainly a printer's error" (Vol. 3, p. 362). At this verse in his 1847 edition of the KJV with commentary, Adam Clarke wrote: "It is likely to have been at first an error of the press, AT for OUT." John Eadie agreed that "strain at" was "probably a misprint in the first edition for 'strain out'" (English Bible, p. 367). The Ryrie Study Bible has the following note at this verse: "This misprint in the King James Version has never been corrected." The Companion Bible's note at this verse referred to "at" as "a mistake" (p. 1363). Concerning this verse in the KJV, Albert Barnes wrote: "The common reading is a misprint and should be corrected. The Greek means, to strain out by a cloth or sieve" (Barnes' Notes on N. T., p. 100). A. T. Robertson commented: "By filtering through (dia), not the 'straining at' in swallowing so crudely suggested by the misprint in the A. V." (Word Pictures in N.T., I, pp. 183-184). David Norton pointed out that the rendering “strain out a gnat” was left unrevised in the 1602 copy of the Bishops’ Bible with the annotations of changes made by the KJV translators, “suggesting but not proving that the translators decided to leave it unchanged” (Textual History of the KJB, p. 44).
"Strain out" is in Tyndale's New Testament, Coverdale's Bible, Matthew's Bible, Coverdale's Duoglott New Testament, Taverner's Bible, Great Bible, Whittingham's New Testament, the Geneva Bible, and Bishops' Bible. The KJV was a revision of the earlier English Bibles. According to the first rule given the KJV translators, what "truth of the original" demanded this claimed alteration in the earlier English Bibles? Why introduce an archaic rendering when the rendering of the pre-1611 English Bibles was already clear? According to the fourteen rule, does this alteration agree "better with the [original language] Text?" If the change was not a clear improvement demanded by the original language texts, why was the change made? The 1873 Cambridge Paragraph edition of the KJV edited by Scrivener has "strain out." Scrivener noted that T. Baskett's edition of the KJV (1754) has "strain out" (Authorized Edition, p. 201). If more copies (a majority) were made of a Bible with a misprint, does this majority text make the misprint the standard for Bibles without the misprint?