I took the Blueprint prep class, went through the Kaplan 180 book, and did almost every practice test there is, some twice, under timed conditions. I was getting 172-178 on practice exams close to the test, really over-exerted myself, then wound up with a bad case of the flu on test day. I took the test anyway, blew my nose every few minutes, got a 172, then got into a top 3 school mostly because the rest of my application was stellar (Harvard, Stanford, Yale folks usually had 175-180 when I applied).
Too late for OP, but for future LSAT-takers, I really recommend Blueprint for your prep class. They have by far the most efficient methodology for doing logic games. I've looked at Kaplan and some other place's methods for solving the same exact games, and let me tell you--Blueprint's methods made the most sense and required the least diagramming. By the end of the course, logic games was by far the easiest section on the LSAT. I'd get 100% every time, no lie.