Light nūn al-tawkīd is a single nūn without shaddah. In the source tables, some light-emphatic cells contain a dash rather than a paradigm form.
FormExampleNote
Heavy emphasisلَيَقِيَنَّnūn with shaddah
Light emphasisلَيَقِيَنْsingle sukūn nūn
Certain light dual/feminine-plural slots—not supplied in the source table
A dash is not a license to invent a conjugation. Record the textbook's restrictions and distinguish light from heavy emphasis.