Camera firmware versions and CHDK settings

Canon A560 GM1.00A - hack ok
Canon A570-IS GM1.00E - later

Now I have a ton of new menu parameters to learn about.  The kind of stuff I need to work out includes:

- How to write the time-lapse script? UBASIC? or Lua?

- Any recommendations for settings for exposure controls, or just let the camera do its thing?
- Should I do exposure bracketing for each time lapse?

- Is RAW capture recommended?

- What is RAW buffer caching and do I need it?

- What about focusing? Can this be preset to infinity anywhere? I cannot find such a setting.
- What about zooming?

- Is there any need for a setting to keep the camera on, and lens out, or will this happen if it is taking photographs?

- Is there anything critical to put in the time-lapse script, other to shoot?
- How about preventing any desire to fire flash?

- Anything else I should know?

I suspect there is more to this CHDK stuff than I realize.