Sorry for the delayed bump, but I just made a batch of these for a friend's birthday. None of the molds are birthday-specific, but the party is casual, so I just went for it and used all 4 designs. I'm sure they won't mind!
I did the first mold (cornucopias) with half a bag Hershey Special Dark chocolate chips and they turned out beautiful, glossy and dark and full of detail. The other 2 full trays plus 1 ornament shape were with each filled with half a bag of Whole Foods Semisweet chips, and they resulted in cloudier and less detailed images -- the best were the ones that had the fewest fine details, aka the Christmas ornament shape. I added mint extract to the cottage pattern and the ornament, and while I haven't sampled one yet, the chocolate left over tasted very nice.
These were easy to use and very cute in the end. I'd like to try them with cookies other than Oreos (or, in this case, Whole Foods 365 chocolate sandwich cookies), but they're definitely built to work best with that exact size of cookie.
Thanks again for the giveaway!