I could have swore the question posted had to do with opening a Post It note so as to learn the original question, not details on switches and peeks.
Yes, there are many (far too many) methods out there to accomplish such things, I'd recommend that you keep it as simple as possible. Study other routines such as Cassidy's "Jazz Q&A" or Docc Hilford's "Invisible Stranger". Then again, more and more of us are doing away with the slips altogether and leaning on actual skill when it comes to Reading people and listening to our natural intuition. Yes, it's scary at first but it allows you to escape the path of doing a magic trick, which is what all the billet work really is. If you go to visit a real Reader, especially in the case of group sessions, you aren't likely to see anything written down. No, these evil charlatans use a more sinister technique -- THEY SIMPLY ASK WHAT THE QUESTION OR ISSUE IS.
Check out Jerome Finley's Gorilla Q&A (if you can track him down) as well as the Black & White books by Neil Scryer (The Practical Psychic's Little Black/Little White Book) in that they will show you an expansion of one of the most basic Reading techniques going -- a method that will allow you to deliver a solid Q&A without billets. My own Easy Reading or the KENS System (see Ron Martin's Palm Reader's Notebook) will take you even further down this path.
BUT, when it comes to working with Post It notes, I stand with what I said originally; those resources have already worked out most of the complication when it comes to the glued edge and coping your peek.