Removed most of what deals with aperture, since it didn't seem to make a difference.
The A530 only has two aperture settings - full open and 2 stops down via a "Waterhouse stop". So you probably would not see much difference if you were only changing things by 1 or 2 stops.
Question about speeding it up: will dumping only RAW, no JPEG do the trick?
You really don't have the option to only shoot RAW - the camera will store the JPG regardless. However, saving JPGs is a lot faster than saving RAW so disabling RAW is a good idea if you are worried about speed.
Would the RAW files have enough metadata for qtpfsgui?
CHDK RAW files contain no metadata - they are just a dump of direct from the camera's sensor. Use DNG format if you want metadata with your images.
