I'd advice you to look through the both parts in each book. Mainly because you've said that your goal is 700+. I'm taking GMAT in late march like you. Currently I've almost finished my quant prep. In case you are curious about it, I started with Kaplan math workbook, it gave me a sense of how GMAT questions look like. After that I switched to
MGMAT guides, which I find very useful for GMAT prep. I've done every single exercise in every chapter and every OG/QR question of course. Now I'm redoing questions which were done incorrectly and also picking questions from question banks on their site. (
MGMAT I mean) At this stage I'm at Q47-48 I guess. Mostly mistakes occur in 700+ questions. So the last part of my quantprep will consist in taking some
GMATclub tests.
I've described my prep in such details since we are in quite a same situation I believe (concerning goals and test dates).
p.s. However, if you are decent at Verbal, that's totally different case, you haven't mentioned your verbal skills.