How best to use Null Space weapons?

[Gwaihir]

waitwaitwait, engine destroyers don't skip shields anymore? do they at least skip armor?
(shows how thoroughly i've researched special weapons)

But re: organic faster build times: yes, true, but I find that even when they outnumber properly designed standard ships by the appropriate amount, even (what i think are) well designed org ships can't do better than break even.