There really isn't any Verbal study material that's meant for test takers in your scoring range. If you'll spend time on Verbal, I'd think your best approach would be just to work through official questions (with only two weeks, don't look at anything unofficial for Verbal) to see if you can pick up on any, say, SC patterns that you're not familiar enough with that the GMAT likes to use. But that might not make any difference. A lot of GMAT Verbal experts have been doing GMAT Verbal for years and still don't get perfect scores, so when you're already very strong at Verbal, it's really not a question of study time or study materials. There are just some very subtle distinctions between answer choices in the hardest questions, and you have to see those distinctions in a test setting. That's a hard thing to study for.
So I agree with Reed above, when he says Quant is probably a better area to prioritize. There's a big difference between a Q50 and a Q51, and a Q51 isn't a realistic target in your time frame, but you might be able to get to a Q50. And I'd again agree with Reed that you'll do best focusing on official questions -- the official Advanced book is a good choice if you know you want to work on hard questions (since your scores are consistent, you probably don't have any meaningful weak areas, so that seems like a good plan, and it's what you'll need to get better at to get to a Q49-Q50). I don't find any major prep companies really do a good job of emulating higher level GMAT math questions -- prep company questions are often hard for the wrong reasons, and aren't similar enough to authentic questions -- but if you were committed to using big prep company products, Manhattan and Veritas are going to be better choices than any others.
You're at a very good level already, so as long as you perform normally on test day (the test will probably seem hard, which is usually a good sign on an adaptive test, so don't let that affect you, and don't worry if you can't answer everything) you should do extremely well. Good luck!