Congrats on your improvement. I have been preparing Verbal using Aristotle SC Grail, Powerscore CR
Bible, SC-CR 1000,solving random questions from GMAT Club and Quant using Bunuel's GMAT Club Math Book. My score in MGMATs always hovered around 590(Q39-41,V31-33).
I analysed the tests and found that I almost got 700 level questions on both Q&V wrong everytime while maintaining a 80% accuracy on the 600 level questions. Afterwards, while preparing, I broke my pattern so that I knew what level questions I was solving. e.g I took a set of 20 S-V Agreement 700+ level questions from GMAT club and used to set the timer to 35 min and used to check my accuracy and tried improving every time
Unfortunately I usd this pattern during the later stages of my prep and wasn't able to do full justice on the D-Day. I scored 630(Q44,V33), which was anyways much better than what I was scoring in the mocks. I'm following the same strategy now and am looking to get my score to 650+ levels after which I'll decide on a date.
Can you suggest any other method I can possibly use to increase my score?