You can definitely score into the 700's with 75% accuracy in both sections on test day. So you are not far off. I would recommend that you go back through the problems you've missed in the
error log. My guess is you'll be better at solving them the second time around. And if not, learn what type of problem it is, the fastest way to solve it, and be able to repeat it on test day. You could litterally see anyone of those questions in a very similiar form. If you are get 90% accuracy you are KILLING the GMAT. Thats only 3-4 wrong in both sections on test day. That is 99% for sure! 700 scorers atleast know how to approach every problem, but are not getting them all correct. There will be times where you will have to cut your losses and move on.
So use your
error log as a learning experience to not only get those problems right, but recognize the problem type, and how to go about solving it. Your ROI here will be very high. I would also recommend that you dont string out your studying for too long b/c you said you want to finish before June. So I would atleast give yourself another opportunity before them. So i would book a test AT LEAST a month ahead of that deadline. Plus, the spots before that deadline will most likely fill up quick, and are probably filling up as we speak. So don't forget to book a date, so you have that time in mind as G-Day. It will not only act as motivation, but direct your studying towards your ultimate goal.
Look at your practice test scores and see if they're close to your goal. Also, be introspective, and be truthful to yourself about how confident you feel with each question type. You should know how to attack every problem like the back of you hand. It sounds like you're doing all the right things, so maximize your
error log, your time, and studying so you can throw down that 740 you're looking for.
Good luck!