If you're using a CF card in an IDE adapter, you don't really need to select the "correct" option -- just tell it that you've an IDE HDD in there, and when you slap a bootloader down, edit menu.lst to have pmedia=ataflash in its proper places.
The Universal Installer apparently doesn't check back to see whether or not the user is lying
so it will quite happily do a full install to flash media with this method! I've done it multiple times -- almost all on The Infernal Dell (a Latitude CPi D300XT from 1999).BTW, my understanding is that ext3 is really the best option here -- it's less likely (vs ext2) to corrupt on a hard shutdown, among other things. (I know I've asked this before but I can't recall -- do recent versions of Puppy play well with ext4 now?)