There are about 15 STC practice tests that come with the book and includes answers. Do not study ANYTHING that is not written by the Securities Training Corporation. It's a waste of time! I strongly recommend the following strategy:
1. DON'T READ THE BOOK. The only section you need to read and understand is the Options section.
2. Do at least 1 or 2 practice tests a day. Take each test twice. The first time, mark all of your wrong answers and read the answer key. You'll probably get a 40% the first time. Don't worry. Take the test again and you should score almost 100% (since you know the answers). Then take the next test and repeat the sequence.
Each test gets progressively harder and builds upon the answers from the prior tests. Tests 13 and 14 are very similar to the actual Series 7.
This technique lets you understand the way the test writers phrase their questions and prepares you for their tricks. YOU MUST DO ALL OF THE PRACTICE TESTS, not just a couple!
Remember, STUDY THE ANSWER KEY!! This is the secret to passing the test!
Everyone I know who prepares this way has scored at least an 85%. You only need a 70% so reading the book is really unnecessary. Plus it will shave off 40 hours from your total study time.
Good luck!
P.S. Time is not a factor. I finished the test in 4 hours and got a 90%!