Hi ZenYogi,
You ask some important questions, but the exact 'data' that you need to properly answer those questions will never be available. Instead, you should think in these terms: one of your real goals on Test Day is to be 'efficient.' That does NOT mean that you have to answer every question 'fast' - it means that whatever choices you make on Test Day, you must make them in an efficient fashion (so that you don't waste time). If by spending lots of time on one question (or on a couple of questions), you end up having to 'rush' through a lot of questions later on in the section (and you end up guessing on them and getting them wrong), then THAT is part of the reason why you haven't hit you score goal.
NONE of the Quant questions that you'll face on Test Day will actually require 4 minutes of 'work'; if a Quant question takes you 4 minutes to solve, then you were almost certainly working in an inefficient way (using a "slow" approach - when faster options were available, doing work in your head, making sloppy mistakes that you then have to go back and correct, etc.). By extension, if you find that "your way" of dealing with GMAT questions is taking a long time, then you likely have to learn/practice new Tactics.
1) How long have you studied?
2) What materials have you used?
3) How have you scored on each of your CATs (including the Quant and Verbal Scaled Scores)?
4) What is your goal score?
GMAT assassins aren't born, they're made,
Rich