Lines to enter Magic Kingdom

At Magic Kingdom, how long after regular entry time (not Early Entry) does it take for the entering hordes to diminish? Let’s say regular park opening time is 8:00. Would there still be long lines at the taps at 8:30? 9:00?

Does it vary depending on the opening time? Like, do the lines stay long longer when the park opens on the early side?

Since they allow everyone into the park the only time I have been really bothered by lines (once the taps are open) has been for special event entry.