I took my car in for service today for the tick. The engineer spent a few hours looking over the car, driving it, recording sound clips, etc. He could not determine the exact cause of the ticking. He said it did not appear to be lash adjusters.
Next, he put the XL-17 in. The ticking did not go away. Perhaps it's a little quieter, but there's not enough difference to know for sure. Maybe it takes some time, I don't know. The engineer asked that I drive the car until 7500 miles, then bring it back for an oil change and a re-evaluation. He also said that Ford will be extending my power train warranty.
Honestly, I'd rather do this for now than have them tear apart my motor not knowing exactly what to look for. Ford knows there is a problem and seems committed to finding and fixing it. Better to let them disassemble their own engines looking for clues than disassemble mine.
In the meantime- I have more info on the XL-17. It's a Ford Motorcraft branded product, and comes in an 8oz plastic bottle with a regular looking Motorcraft label. I also found an MSDS for it that says what is in it. I've attached it to this post for whoever is interested.