you can finish them. on a few of the days, you may need to do two tests. start your day off with a full natural science test (bio, gc, oc consecutively) and maybe work on your weaknesses right after that. you can definitely count that as studying because of the solid explanations that they give. you will definitely learn alot.
they even have a button for 'unseen questions' which are questions that haven't shown up on any of your practice tests. you can do those when you're done with the tests.