There is not much difference as far as remastering. There are a couple of modified commands when building the iso, and they are covered in the standard remastering guide on this site.

Changing default boot parameters and boot messages is easier since you no longer have to loop-mount the boot image to access the files for editing.

They would be located in your remaster's .../master/boot/isolinux rather than in .../master/KNOPPIX/boot.img