Thanks, guys, for your lovely and helpful replies.
Since yesterday I've been taking small to medium size sets of Official questions (from OGs more than ten years old so that I don't come across repeat questions) from each of the five quant (PS, DS) and verbal (RC, SC, CR) sections and answering them with an eye on the timer.
I'm doing fine in both the quant sections (so I've decided that I'll tackle the quant section first in the next official mock I take; I took the verbal section first yesterday and totally bombed it). I'm doing very well in SC (average time of a little less than 1 minute), and pretty decent in the CR and RC sections (2 to 3 minutes). Will take a full-length mock in a day or two and let you guys know how it goes.
These timed sets are helping me understand that there's no rule that I need to do every question in under two minutes. I'm also learning that I shouldn't rush unnecessarily (saw a couple of Youtube videos from Reed Arnold of
Manhattan prep taking the exam real-time, and they were really helpful--good to see that even expert test-takers fall behind on time, get confused by certain questions etc.). I realize it's totally okay to slow down for a certain question and speed up on a later question that's up your alley.
I'm building up my confidence slowly but surely. I'll hopefully be game-ready by January 4th.