Dear Nigel and Jenny,
I did it! I took overall 7.5 (L. 7.0, R. 8.5, W. 7.5, and S. 6.5 respectively) !!
My best score in writing was only 6.0 before taking your course! I even took 5.5 twice in this section.
I should have known your course much earlier, indeed.
Thank you very much for your help!!!