Ah, my OSD menu looks VERY different from what's shown in the user guide. It's missing a lot of options - including RAW--> and FILESPACE-->
I'm using the only version of CHDK for S5 ver 1.01b that I saw. It's the Stereo something version.
Is there a better version for the S5 that is not listed on the wiki page - one that can calculate how many RAW files remain?