We took a few years of development before we entered the edible ink / frosting sheet business, with a focus on providing the best quality edible inks and frosting sheets. We believe we have perfected this combination, and our customers are very satisfied with these products. We then moved on to chocolate transfer sheets, and released our first product for chocolate transfer a few months ago (item 511-001-01), which is perfect for white chocolate transfer. It is not cocoa butter coated, so only works well with white chocolate.
As for a great product to get image transfers to DARK chocolate, you need to use cocoa butter. The cocoa butter is not in the inks, it is on the transfer sheet. We have has some customers tell us that they spray cocoa butter to a non-cocoa butter coated sheet and they are happy with that for dark chocolate, but our approach has been to make a new style of chocolate sheets that are pre-coated with cocoa-butter and will be ideal for transferring images to dark chocolate. We will update the item # when that product is released, hopefully soon.