Working again with the Douglas/Newcastle data, I generated PCA score plots using 100, 500 and 990 words; they've virtually identical, and have the Newcastle texts grouped towards the top right, and the Douglas texts at the bottom left. Generated PNG images from the results; I found that these images, and all the PNGs I'd saved before, were very low-res and ugly, so I experimented to try to find the best output settings. It turns out that only the ugly low-res defaults have the right aspect ratio; as soon as you specify a higher DPI in the Options dialog (from the Save dialog), you get a square image, so it looks a bit odd. In the end, I think I'll have to screenshot the graphs in Minitab itself, and save the screenshots. How silly.