The HECK, with lockwashers -- with all the work that goes into one of these things, it,s, well worth the price of nylocking nuts !!!
They come in both fine, and coarse threads and after working on aircraft for many years, I can,t imagine useing anything else !!
I suggest after trial fitting everything, with plane nuts and flat washers, do your final installation with NEW nylock nuts, and flat washers -- I say "after trial fit", as nylocks loose there locking ability after being installed and removed a few times..
Very nice job "Hiker" , and love your cabin -- where is it ?? Bill H....