Upload & Sell: Off
Start at 2400 DPI. On my v700, there is no meaningfull difference in quality between 2400 and 3200. Then try stepping down to the next lower and see if there is a difference. Tiff vs JPEG depends on how much processing they need. One option is a hybrid. Scan to TIFF, process the images, save the final to JPEG and discard the TIFF. If they are family pics, etc, you will probably not be going back later to reprocess.