For math, I would strongly recommend using the OG alongside the
Manhattan books. But I don't feel as strongly about this for SC. GMATLA offers an interesting compromise, though doing all of the recommended questions listed in the guidebooks wouldn't hurt you by any means. In other words, I don't think that it would put you in some artificial advantage to attempt specific types of practice questions from the OG shortly after reviewing them in a guidebook. And don't worry about running out of questions. There's the OG 13, OG Verbal, Manhattan's online SC question bank, the GMATClub SC forum, and the two GMATPrep tests.
And, as GMATLA also points out, you probably will need to revisit the book. In fact, I usually urge members to read Manhattan SC at least twice.