I think you should be okay with the material you have listed Manhattan books
are quite comprehensive, and provide a detailed, conceptual coverage. I wont set too much time/effort for Kaplan
Math book..may be after you are done with OG and Manhattan ( including some very good questions in the online question bank that you will get access to with your purchase.)
I didnt/couldnt put Manhattan CR
strategy to good use.. (it bases itself on diagraming) And that's when i switched to Powerscore CR
. I liked the book..it gives a very good coverage of all types of questions etc. I think , since you have already ordered Manhattn CR, go through it, do all practie questions, and i f you do think you require more training then go for powerscore.
Take a GMAT Prep test soon..the earlier you know what your weaknesses are, the better. I always thought Maths would kill me, and Verbal would be a smooth ride.. my diagnostic showed me otherwise..and I made it a point to be thorough with verbal, and gave it as much time , if not more.
Last piece of advice: Time flies! Try and stick to a schedule..keep enough buffer.. pretty soon the 4 months would be over
Well, mine did, and I cant believe am so close to test day now