Nice dear, as far as i think one should employ this formula or technique when he has less time to cover the whole syllabus. Presently, as it is August, 5 to 6 months are remaining so the first object should be to cover the whole syllabus or at least go through any authentic book like Mazar ul Haq's book. Beside, If u don't follow the topics in sequence then it becomes very much difficult to comprehend and grasp the subject. So i suggest that at least once go through a book and then cover the previous 10 to 15 years question papers. Exam Cram series by Jahangir also helps in this compass. Thx