Dramatica recommends at least five Story Drivers: before (or to start) each Act, and as the closing event. But say a story had six or seven drivers. Would four of them still have to line up as turns into each act, with the fifth as the closing event?
Or could seven drivers be evenly spaced between the four acts, with only the Inciting and Closing events lining up with act breaks?
Short answer: Yes
All act turn driver events must occur between the Inciting and Closing events in the Overall Story thoughline, which means the inciting and closing events cannot line up with act breaks because the open and close the story's argument. You can have material before the inciting event (prologue) and material after the closing event (epilogue) if you want.
The driver events in the Overall Story throughline move the throughline forward. While you can have more than the five drivers, they should be in addition to the locations of the five standard drivers (opening event, first, second, and third act turns, and closing event).
Each of the four throughlines has three act breaks, which gives you a total of twelve act breaks. When all four throughlines are synchronized, the story will seem to have only three act breaks. However, one can easily make them asynchronous and have more act transitions (though the drivers only control the Overall Story throughline). This technique is often used in television so that commercial breaks have the feel of act transitions.