For the time being (and as an option) I might suggest you place the attached 16x9 grid file into the Grids folder in the CHDK folder. Load that grid from the OSD parameters > Grids menu, then shoot full-size (4320x3240) and you'll be able to crop to what you composed using the 16x9 grid. No, not a perfect solution, but I display this grid by default just so that I can decide at the time I take a photo if I want to use it or not.
Also, as I am an SX130 user, I would like to get a DNG file from an SX150 to study. Any photo would work, it doesn't matter the content, I just want the file to experiment with. Could someone please post one somewhere where I could download it, as it would be too big (in MB) for my email to accept. A big thanks to anyone who can help me out.
Mike