In the positions where Light Noon is allowed, the vowel immediately before the emphatic Noon follows the same pattern as with Heavy Noon.
Light NoonHeavy NoonPosition
لَيَفْعَلَنْلَيَفْعَلَنَّmasculine Ghaa'ib singular
لَيَفْعَلُنْلَيَفْعَلُنَّmasculine Ghaa'ib plural
لَتَفْعَلِنْلَتَفْعَلِنَّfeminine Haadhir singular
Key difference: Heavy Noon is doubled; Light Noon is a single silent Noon.