RE: Nylon VS metal cable pull pull??
Stretch would be my only concern. I'm sure nylon has improved over the years, guess I still wouldnt trust it. I use vinyl coated steel fishing leader wire, ~40lb. If its for small electric, that would be different. I think there is a carbon fiber thread or maybe some super duper fishing line that would work. Just speculating. Somebody else probably knows better than I.
Edwin