Thanks for your suggestion but since I don't own a Casio key board I probably won't implement this feature. It is Open Source so you or others have the freedom to make the changes your self. You could also try using a midi sequencer and edit the midi file your self to copy and time shift the piano part as required to make your keyboard light light up early. I am interested to know that the lights work for you though.
However I have just completed something you may find more useful for beginners and that is to name the notes. One of the key skills in learning to sight read music is to keep your eye on the score and not to constantly look down at your hands. If you add a strip labeling the notes like this one

Naming the notes should help with this skill as you can key your eye on the score. Are you are on Linux if you are you should be able you compile the latest code from svn and see if that meets your needs?
svn co
https://pianobooster.svn.sourceforge.net/svnroot/pianobooster/trunk/PianoBooster If you do try this code can you please let me know if this works OK for you.
Louis