2. Should i slightly more than average time on any 700+ questions i encounter while i am still under question 15 in the real test?
No, for three reasons. First, the earlier questions are not worth more than the later ones. Second, you have no idea which are 700+. (Even the test makers have to test these questions on a thousand real students to determine the difficulty level. You can't just look at question and know.) Third, the 2 or 3 hardest (and easiest) questions on your test will count less towards your score than all of the other questions. (The "outliers" count less.)
In general, most quant questions should fall between 1 minute and 2.5 minutes - enough time at the lower end to really give it a shot and minimize careless mistakes, but not so much time at the higher end that you shoot yourself in the foot on later questions.
If I finish a quant question and think it hasn't even been a minute yet, I check my work.
1. How long do i spend on a quant question before i give up?
The real decision point is at the approx. 1 min mark. Yes, 1 min, not 2!
Read section 4 of this article to understand why:
http://www.manhattangmat.com/blog/index ... nt-part-1/(Note: section 4 is in the second half of the article.) And then read the rest of the article and start doing what it says. :)
The key overall idea is: if you don't know what you're doing by the halfway mark, then you're not going to finish this one off (let alone correctly!) by the 2 to 2.5m mark, so you might as well stop now, try to make an educated guess, and move on. Save that time and mental energy for lower-hanging fruit, since all of the questions (except the very easiest and hardest in your mix) are worth the same.
It sounds like you know what you need to do in terms of the material - and do let me know once you take another test. Don't take a test more often than once every week or two - you already have data from the first test, so it's not worth it to take another so soon after!