I also only had one drug ad on my whole test, with 3 questions attached to it - I think in my 4th or 5th block. The best advice I received was to do the best I could throughout the rest of the block and when I encountered the abstract/drug ad questions, mark them, save them until the end, take a glance through the question and the text, and just guess - I must have picked C for all 3 of them. We'll see how that worked out in a few weeks.
I spoke to several people who did well on CK on how to strategically get through these questions - because they are so long and require a lot of analytic thinking in a short span of time, which is so terrifying on test day. What I gathered from these conversations with those who actually practiced and worked through the Uworld examples was that the probability of getting them right is no different from if you just guess on all of them. Additionally, spending time on reading abstracts and figuring out how to answer any number of questions they could pose to you about them on test day doesn't actually increase your gains when it comes to high yield material you could otherwise be studying.