Hi Cybercom,
I am currently running the Jucifer modified Allbest build.
I first set Focus Lock. Then I go into the photo options and configure the focus bracketing distance for what I need. "Value" is multiplied by the number of millimeters you choose. Configure either to bracket forward focus (+) or back (-).
If you do not set Focus Lock before you engage focus bracketing in CHDK, you'll crash the camera. However, once you do set Focus Lock, then take your shots, it seems that you can unlock the focus and reset it without first exiting the focus bracketing mode in CHDK. (Curious.)
Obviously for stacking it needs to be done on a tripod, as all of the shots are meant to line up absolutely perfectly when doing the stack in software. But it still has artistic use on it's own showing a simple progression of shots. Macro is fantastic in increments of 1 mm, and increments of 300 mm (approximately one foot) from close to infinity is also interesting when sighting down a tree line, for example.
The Custom Timer can be configured to delay and then shoot a preprogrammed number of shots, but unfortunately only up to ten.
You can see in the LCD the focus change with each shot, which is a blast.
The shots then need to be compiled in software such as CombineZM (freeware). I have not used it to stack any shots yet.