The chdkptp ptp sync method is very clever but also, fundamentally, straightforward.
In a much simplified nutshell, at a (different for each camera) point in time both the PC operating system and camera operating system times are measured (in ms) and recorded in PC memory. For the camera it is the count of ms that have passed since it was turned on & for PC it is the count of ms from a particular date in history that I don't remember.
At the present time a new PC system ms time count is measured & recorded (on the PC). In order to make a calculation (on the PC) of what the unique present time camera system count (since turn on) should be (at this present time) we take the difference of both PC system time counts (present less historic) and add that to the original camera count.
It takes a finite time to send this calculated unique count from the PC to each camera (one after another) so an unmodified calculated count sent to any camera would already be less than that of the camera operating system count at the time of receipt. The unique PC calculated count for each camera is therefore increased by a number of ms that is equal to (or greater) than the maximum period required to send the unique count to all cameras.
On receipt (at the camera) of this unique PC calculated count, the camera waits until its operating system ms count is equal to the one sent to it by the PC before opening the shutter.
There's a bit more to it than that but, even if an equivalent were possible in digicamcontrol, it'd probably take the author quite a while understanding the detail & coding it.
The time to automatically move the mouse and click a button is probably not insignificant.
You might need to be careful wiring those remote shutter cables together
http://www.agisoft.com/forum/index.php?topic=2081.msg11290#msg11290Edit: there is a link to a breezesys article in that Agisoft thread that includes a diagram with the addition of a diode (for each camera) when wiring the focus/shutter release cables together which (presumably) limits the potential for current flow (or voltage application) between cameras that could, potentially, cause problems/damage.
