1) Unzip.
2) Either use the command-line "unpackimg ", or simply drag-and-drop the image. This will split the image and unpack the ramdisk to a subdirectory.
3) Alter the ramdisk as you like.
4) The repackimg batch script requires no input and simply recombines the previously split zImage with the newly packed modified ramdisk using all the original image information (which was also split and saved).
5) The cleanup batch script resets the folder to its initial state, removing the split_img+ramdisk directories and any new packed ramdisk or image files.
There are two optional, advanced command-line arguments for repackimg: "--original", which will cause it to repack using the original split ramdisk instead of repacking, this is useful for testing or trimming dumps; and "--level" with 1-9 and possibly 0 allows changing the compression level used to repack to more closely match the original.
Usage is similar for the Android and Linux versions, again, just review the release notes for them.
Hopefully this is some help to someone. It's been extremely useful for me in my messing around with kernel ramdisks, which is why I created it in the first place.