You have provided a lot of information and I'll try to hit some of your points, but may not address all of them...

First off, I would not take the real test without finishing OG11. I say this because the last 20-30 questions of each section are significantly more difficult than the other 100 preceding them. During my studies, my hit rates were in the high 80s and low 90s in each section...until I hit the last 20 or 30 questions. For DS, my hit rate went from 90-100% down to 57% in the last 20 questions. It will give you a clearer picture of the types of problems you'll see. If you really cannot finish the entire book from end to end, then at least take the last 20-30 problems of each section.

As for the variety of other things going on in your life, you can search this forum and find other members who have successfully beaten the gmat with similar time/stress pressures - new baby in the family, just married, 3 kids and a job, etc etc. Keep up your motivation and look to this forum for encouragement if you get disheartened. It can and has been done before!

The MGMAT material is supposed to be really good. I only used the SC book myself, but it is considered the SC bible. Since that is one of your stated weaknesses this book should help you greatly. In addition, you get access to 6 MGMAT cats if you buy this book. I consider the MGMAT CAT to be the next best after GMATPrep.

For more information you can check out Eric's blog here:
https://www.beatthegmat.com/720-96th-per ... t-t13.html

And my own blog here:
https://www.beatthegmat.com/errors-and-l ... t4899.html