Need an advice [GMAT Exam on 25.01]

Hi dear experts,

I've been preparing for the test for a while with interruptions etc. After trying out much unofficial stuff (means, I've done all official Q's both in quant and verbal guides, and for practice did also Q's from other sources such as Kaplan, Princeton, 800Score etc) I observed a decline in verbal scores and particularly in the CR section (CAT scores are stated in my signature).
That's why for the last couple of days I've focussed on exclusively official questions from GMATsoftware (I've downloaded an extract of all questions Exam 1&Exam 2)

So, my strategy for the next two weeks includes solving every question from the question pool stated above and taking 2 extra gmat tests (Exams 3&4) on 14.01 and 18.01.
Do you think it's a viable strategy for the next two weeks ? (Target score 680+).

My problem zone ) is verbal part and particularly RC, I've been doing pretty good on SC and CR part, but as I've already said CR skills have become inept after doing so much unnecessary unofficial stuff.

I would appreciate your advice regarding preparation and test day.

Kind regards,
Mike