Look up previous AMCAS verification threads. If you submit the day it opens for submissions, you generally get verified very quickly. After that, the wait time gets longer. At the height of the season, it can take a month or more. Here's the link to last year's thread: Official AMCAS Verification Thread 2016-2017
There's no hard limit on secondaries. Sure, it's good to get them turned around ASAP. But I got to the 4-6 week point on one of them and still got an interview (didn't get in but that had more to do with the interview). It's always better to submit quality over quantity - but that's not to say you should or can perfect every one of them as that would take prohibitively long. I would say 2 weeks is a good rule of thumb but the difference between the 14th day and 15th day is solely in pre-meds' minds. Remember, quality.