Just so you know. Early 325 way way back by Oregon used a 5/32 file too. Was oregon LG33 full chisel.
I started using a 3/16 file for the newer bigger cutter 325 uses today.
Adding that hook for softwoods it did cut faster.
I even tried it on a firewood cutter. He told me I dont know what you did to it but keep doing it.
But that LG33 cutter is bigger then the little NANO cutter.
I used to do chain build offs on my old website years back. So I got to try alot of different things like that. Even square filed 3/8LP and 325 in full chisel
Some stock 325 chains from back then. All used 3/16 except for LG325 stock 5/32