Here's my philosophy: I have studied the day before the exam for EVERY test I have ever taken in my life, and that is what I am used to, and it seems to work pretty well. Obviously I am not going to pull my normal 8+ hr study day the day before my MCAT, but I will reread all the notes I have done, and flip through all the books I have studied, draw out some ochem mechanisms again, just to bring everything back to the forefront of my mind.
More importantly, I do not take the day before my practice full lengths off, so I want my real deal MCAT to be the same feel.