Why should he tweak the lightning if he simply could change the tilemap for the Lakitu boss in the asm-file?
Open the asm-file in a txt-editor or something like that, look for the "Sprite graphics routine" and change the following:
Originally posted by asm-file
TILEMAP dcb $CE,$EE,$EC,$EE,$A8,$EE,$A8,$EE,$A8,$AA,$A8,$AA
$EC would be 3EC in your 8x8-tile editor. It's where the lightning graphics are (part of) and the head for the lakitu-boss as well so you have to change that value at least. IF I'm not missing something, that should be it.