Well I ended up going part time at UCLA, b/c they have an excellent part time program. They also allow you to compete with full time students for all jobs, and they don't have strict rules like some other programs. I also want to stay in the same industry, and simliar job role, etc... UCLA is ranked #2 in part time programs. And for this reason, it's why a lot of top MBA programs either don't have part time programs, or have strict rules that hurt their part time rankings. See them here: us-part-time-mba-rankings-class-profiles-and-comparison-84898.html?fl=menu
It's a big deal at the schools you've mentioned b/c they really don't want part time students competing agains their full time students b/c this will hurt their full time ranking. Obviously, this is their bread and butter, and why they have great reputations. But their part time programs can be somewhat limiting, but you get that reputation on your resume.
Although, I have heard of many students leaving their job after their 2nd year in the part time program, taking an internship, and then either trying to turn that into a job and working while they finish up their last year or school... or go to their last year of school is an accelerated way (while not working) and then taking a full time job with that company. It can be a little tougher though b/c recruiters aren't as familiar with it.
All this being said, you are correct, a 630 will put you outside the 80% range for both full time and part time at these programs. SO i would recommend that you put all your effort into your GMAT and work to hit 690+. At that point, you can drill down on what programs will be right for you. In the meantime, go to an open house or two (for both programs), talk to some alums, browse our forums, and really figure out what will be best for you. There's a lot to consider, but fortunately you are starting at a great time of year to have plenty of time for round 1 applications at the schools of your choice.
As far as gruduation times, speed, and if they will allow it, all schools are different. You will have to contact them directly.
Good luck, and let me know if you have any other questions.
New to the GMAT Club? <START HERE>Find out what's new at GMAT Club - latest features and updates
My GMAT and BSchool Tips: