Concerning the "largeness" of the plates of Mormon and Moroni (Mormon 9:33), Robert F. Smith notes that a surprising amount of consistent information can be gleaned from eyewitnesses: Joseph himself gave us the length, width, and thickness of the whole set of plates as 6" x 8" x 6" in his famous Wentworth Letter. . . . Joseph Smith, Martin Harris, and David Whitmer all suggested that the plates were "not quite as thick as common tin." . . . Tin in the early nineteenth century may have been around .02 inch or less . . . thus, each Book of Mormon plate could have been between .015-.02 inch thick. If each plate (allowing for air space and irregularities) occupied from .03-.05 inch, the six-inch thick collection would have contained between 120 and 200 plates. If each was engraved front and back, there were 240 to 400 surfaces. [Robert F. Smith, "The 'Golden Plates," in Reexploring the Book of Mormon, pp. 275-276]
“If Our Plates Had Been Sufficiently Large We Should Have Written in Hebrew”
According to Cleon Skousen, one of the most remarkable things about the ancient alphabets was their capacity to record a voluminous amount of information in a small amount of space. They were almost like some kind of shorthand. This is dramatically demonstrated by a Jewish convert to the Church, Henry Miller, who discovered that the entire Book of Mormon could be written on 41 pages if the Hebrew alphabet were used. . . Photographic plates of Henry Miller's translations will be found on pages 40 and 41 of J.M. Sjodahl's book, An Introduction to the Study of the Book of Mormon. But even these forms of writing were too voluminous for the writers in the Book of Mormon. [W. Cleon Skousen, Treasures From the Book of Mormon, Vol. 1, p. 1027]
Mormon 9:33 If our plates had been sufficiently large we should have written in Hebrew ([Illustration]): Hebrew translation of 2 Nephi, Chapters 5:20 to 11:3 inclusive (about 14 and 3/4 pages of the English version). Used by permission, J.M. Sjodahl. [L.D.S. Church, Book of Mormon--1962 Seminary Edition, p. 569]