If I am brutally honest here, and I generally don’t like to say this but I feel it’s nearly impossible to achieve your target within the given time unless you start compromising. Whatever I say next doesn’t hold true, if you are already near your target or 30-40 points away, because then you might have some fair idea on what needs to be done.
But if not, then you are targeting somewhere around 98% overall, needing an average of 85 sectional score across all three. And to get there you atleast need to start hitting 70-80% accuracy at hard level questions within 16 days (weekends).
So in case if you are looking for 70-100 points improvement, my first advice is to start making feasible milestones next. Ask yourself if you would be able to score an avg 655 consistently by end of next 2 weeks, avg 685 in 4 weeks and avg 705 in 6 weeks? As you might not be able to learn anything new in the last week. Realistically this is possible if you spend good time on your practice, but with your schedule, if you ask me can I get there without spending the required time, then unless you are quite sharp, it’s super difficult.
Next question you need to ask yourself is how important is it for you to get that 705? Your answer to this will help you reach to what’s feasible. I know that job could be demanding but then you need to evaluate the ROI you will get from spending more work hours now vs needing that high score? There’s no right answer here, but it will help you decide what you want to prioritise as it would be hard to give enough time to both and come out on the better side. As it’s true with work where good time investment gives you better outcomes, GMAT prep is also not that different.
I agree that these prep courses might seem lengthy if you are running tight on time, I gave up too multiple times after starting as I didn’t have that much patience. My solution to this problem was to get hold of books like
Manhattan Prep where I can learn all the fundamentals quickly and then learn by practice by solving questions on GMAT Club for months until I was clear with most of the concepts in that topic and was hitting good timings on them.
Now this kind of practice alone might take hours, like if I have to put a number, it’s easily 3-4 hrs consistent daily practice for 8 weeks to improve somewhere b/w 50-100 points on the higher scale. And considering you have still work to do in DI, you need to add in the learning curve for one of the most challenging section in GMAT.
Take some time to think through these points and decide what feels like a realistic target for you based on your current state. I’m happy to share my thoughts whenever you want.