With 3 weeks out and a 665 → 705+ jump to make, I'd keep it simple: the free GMAT QBank (1233 questions) is honestly solid for what you need right now. The question style and difficulty across Manhattan's products is fairly consistent — the paid QBank gives you more volume, but at this stage you don't need more volume, you need targeted practice on your weak areas. Your Verbal score (V82) has been steady across both attempts, so the goal should be identifying exactly which question types are costing you points — is it CR assumptions, RC inference questions, something else? — and drilling those specifically.
If you find you're blowing through the free QBank questions in your weak areas and need more reps, then the $39 QBank is reasonable. But I'd skip the 8th Ed book and the On Demand Course for now — with 3 weeks left, you don't have time to absorb a full course, and practice questions are what move the needle at this point. For what it's worth, during my own 725 prep I found that doing fewer questions but thoroughly reviewing every wrong answer (writing out why each wrong choice was tempting) did more for my Verbal score than just grinding through hundreds of problems. Focus your energy on the
error log more than the question count.
You've got a real shot at 705+ — that 645-to-665 jump shows the trajectory is there. Good luck on 02/03!