Half is too much. Try to get an accuracy of 80%. How? Try attempting less in a few mocks.. but focus on accuracy. Dont try to score 350. Try to tick the ones you are confident in. No guessing.
You have to balance this.. hence mocks are vital. The process of elimination is crucial. But it can lead to guesses. Try not to make many guesses. You have to make a few. But not much.