What's the difference between [sil] and [pau] in NNSVS labelling?

[Kawaiine Is Queen]

I don't know which to use to label silence between lyrics, what's the difference?

 

[Halo]

That you don't need to worry about sil. Use pau for "actual" silence/pauses, use cl for held consonants like datte or meccha or what have you, glottalstop (or, whatever it is now in the current jp hed-- q? gs?) for glottal stops. But there's not really a reason to use sil.