Yes, except that I change the "Device" setting to "Kindle Paperwhite" instead of "Kindle 1-5", and I usually convert the first 5 pages or so to make sure I have the borders right before I convert the whole document. The idea of cropping the margins is to set them such that page numbers and chapter headers are cut while retaining the text. You shouldn't need to touch the left and right margins most of the time, only the top and bottom ones. Use binary search.