What's the most effective way to use Manhattan Strategy Guide?

Hi,

I tried to search for a similar thread about this but it seems like there is none that really answer the stated question..

As far as I am concerned (by reading about gmat-prep on the internet and forums like this) the OG is the most crucial tool within gmat prep. But as it also seem to be important to fulfill the most fundamental step in the "maslow's"-like gmat-satisfaction ladder I've begun my GMAT-journey by reading the first four Manhattan prep-books and completing their problem sets.

I feel now that I need to increase my efficiency. I have about 1 month left (should be able to study for about totally 100h from now), and feel like I want to begin doing my OG-problems as soon as possible! But I also feel that I need to complete all my Manhattan Strategy guide books!

Therefore, my question is; What is the most effective way to use my Manhattan Strategy Guide?
-Is it by simply read all books and do all the problem sets?
-Is it by only do the problem-sets and if needed look up the things that you feel you don't completly grasp well enough?
-Is it by read the whole thing and do about 3-4 questions in the problem sets and then move on? (since doing all the problems takes a while)

Looking forward to hear your thoughts about this.

Regards / A