Studying all of the references within the "Self-study reading and video list" is imperative in order to pass the exam. The exam includes questions from each and every one of the references.
Use the free practice test as a good gauge of whether or not you are prepared for the full exam. Most candidates who have taken the full exam thus far obtained scores that were within +/- 6% of what they had scored on their very first attempt of the practice test. Subsequent attempts of the practice test have not been a useful predictor of full exam performance, since those additional attempts now focused on studying only for those 11 questions of the practice test, and not on studying and examining knowledge of the entire curriculum.
You will be required to know the UL system nomenclature for through-penetrations and for fire resistance rated joints. Examinee can have reference material on hand with that information.
You may want to have a basic pocket calculator on hand to assist with some very basic arithmetic calculations.
You are welcome to have as many reference documents with you as you would like when you take the exam, either as printed copies, or as electronic documents, or both. Note, however, that the timed nature of the exam will make it impossible to go searching for answers if you don't already know where the information specifically resides in the self-study references. Thus, having access to reference documents during the exam will not provide any great increase in the probability of passing if you have not previously familiarized yourself completely with the material in the self-study references.
It is highly recommended that you test your computer hardware and software for smooth functioning with the online proctoring service. You can do that at

International Firestop Council