Here are some of the statements by KJV-only authors who use this argument.
In one form or variation of the argument from a tree, stream, or line of good Bibles, William Byers claimed that the KJV is the seventh translation in the English language from the pure text and is thus "purified seven times" (The History of the KJB, pp. 9, 23, 97-98). William Byers wrote that the Geneva Bible was the "sixth translation" (p. 9), but later he wrote that "Geneva is five" (p. 97). Although beginning his list with Wycliffe's Bible, Timothy Morton made a similar claim to that of Byers when he wrote: "Each of these Bibles was (and still is) a valuable translation, but the King James of 1611 is the purest--the seventh and final purification" (Which Translation Should You Trust, p. 9). Doug Stauffer maintained that "the King James Bible became the seventh purification of the English translation in fulfillment of this prophecy" [Ps. 12:6] (One Book Stands, p. 282). David Sorenson claimed that “the KJV was the seventh refinement of God’s Word in English from Tyndale” (God’s Perfect Book, p. 137). David Sorenson declared that the KJV “has been purified at least seven times as it were in a furnace of earth” (p. 116). Hugo Schonhaar asserted: “This writer believes that God used the previous seven translations as a purification of the English text” (Woods, King’s Bible, p. 270). John W. Sawyer declared that the Geneva Bible was “the fifth refining of the Word of God in English” and that the Bishops’ Bible was “the sixth refining” (Legacy of our English Bible, pp. 8, 9). Timothy Morton asserted: “From Tyndale’s translation in 1525 to the King James Bible of 1611 the text of the English Bible went through a period of purifying” (From the Original Text, p. 7). David Cloud also suggested that “a purification process occurred in the 16th century as the Scriptures came out of the Dark Ages into the era of printing” (Answering the Myths, p. 54). David Cloud claimed: “We must remember that it took 230 years for the Bible to be perfected in English, from the time of the first translation by Wycliffe to the King James Bible of 1611” (Dynamic Equivalency, p. 58). David Cloud asserted: “From Tyndale to the KJV the English Bible was undergoing a process of revision and purification” (For Love of the Bible, p. 185).
William Bradley stated: "The King James Bible was the seventh major English translation of the Scriptures" (To All Generations, p. 29). William Bradley also began his list with Wycliffe's Bible and included Tyndale's, Coverdale's, Matthew's, Great, and Geneva Bibles, but he omitted the important Bishops' Bible of which the KJV was officially a revision. In his later book, Bradley actually listed a total of eight English translations in two consecutive paragraphs [Wycliffe's, Tyndale's, Coverdale's, Matthew's, Great, Geneva, Bishops', KJV], which actually made the KJV the eighth translation (Purified Seven Times, p. 116). Nevertheless, Bradley claimed: "When the seventh major English translation of the Bible was published, the Word of God in English was complete; it was perfect" (Ibid., p. 131). Ed DeVries also asserted that the KJV is "the seventh major translation of the Bible in the English language" (Divinely Inspired, p. 28). In his list, Ed DeVries listed Wycliffe's, Tyndale's, Matthew's, Great, Geneva, Bishops', and KJV, but he omitted the important 1535 Coverdale's Bible. After citing Psalm 12:6, William P. Grady claimed that the KJV is “the seventh major English translation,” purified seven times (Given by Inspiration, pp. 105-106). James Rasbeary asserted: “The King James Bible was the seventh and final English Bible—‘pure words … purified seven times” (What’s Wrong, p. 92). Phil Stringer also proposed: “It took several decades and seven major translations (Tyndale, Coverdale, Matthew’s, Great Bible, Bishops, Geneva, King James) in order to get the pure Word of God in English” (Carter, Elephant, p. 47). Ben Pierce claimed that “the printing and publication of the King James 1611 would be the 7th and final completed English translation” (Valiant for the Truth, p. 106). Joey Faust listed the KJV as the seventh English translation, and he asserted: “The Authorized Version (i. e. KJV) is the final purification. This is a fulfillment of God’s promise to preserve His pure words” (The Word, p. 45). T. S. Luchon also used this argument, listing the KJV as the claimed seventh English Bible (From the Mind of God, p. 66). G. John Rov asserted: “This ‘vine’ (John 15:5) of Bible translations into English that were the growth and issue of the King James Bible, numbered six, making the King James Bible the final translation” and “the seventh, according to Psalm 12:6” (Concealed from Christians, p. 115). After citing the fourteen rule for the making of the KJV, Laurence Vance claimed: “The seven English versions that make the English Bibles up to and including the Authorized Version fit the description in Psalm 12:6 of the words of the Lord being ‘purified seven times’ are Tyndale’s Matthew’s, Coverdale’s, the Great Bible (printed by Whitchurch), the Geneva Bible, the Bishops’ Bible, and the King James Bible” (King James His Bible, p. 84). Michael Hollner asserted: “God used a ‘purified seven times’ (Psalm 12:6-7) refining process during all the English translations prior to the 1611 version, and used men to refine the 1611-1769 versions to give us a final product” (King James Only Debate, pp. 442-443, 2021 edition).
Gail Riplinger also adopted her own variation of this same KJV-only argument. Gail Riplinger contended that “the English Bible was ’purified seven times’ and that “the KJV is its seventh and final purification” (In Awe of Thy Word, p. 131). In her book, Riplinger maintained that “the English Bible’s seven purifications are covered, including, the Gothic, the Anglo-Saxon, the pre-Wycliffe, the Wycliffe, the Tyndale/Coverdale/Great/Geneva, the Bishops, and the King James Bible (p. 33) [see also pp. 131, 843, 852]. She proposed that “the KJV was the seventh polishing of the English Bible” (p. 137). This seems to be one of the main themes of her KJV-only book. Would it be acceptable KJV-only math and reasoning for four translations to be counted as one? Gail Riplinger asserted: “English Bible, which saw its seventh and final purification in the King James Bible, can never be updated (Ps. 12:6, 7)” (Hazardous Materials, p. 29).