3 week study plan

Disclaimer: I am a 690 scorer who is going to retake and I am aiming +700.

In my opinion your plan needs revision.

First, exclude the McGrawhil tests and Cliff Notes. They are not highly regarded materials.

You will need MUCH more time to study the MGMAT SC guide, even if we consider an 8-hour study day. It is very dense and demands a lot of time. I would say that it is OK to dedicate one day for the MGMAT CR or MGMAT RC book, but definitely not the SC guide.

Take one GMATPREP right away to really have a true diagnostics and so have a clear picture on which subjects to focus.

And finally, only schedule your GMAT test when you are already scoring a 730+ on the GMATPREPs.

Good luck on your marathon !