If I have Industrial Sectors, I will build them on tiles with large manufacturing bonuses (>100%), or even 100% tiles if my economics are good enough to stand it. They usually are, by the time I get IS. This presupposes the eco to support the mfg. costs.
Fanatically. I find that the ai's, so called, rarely use it at all, and never effectively (yet?). So with relatively modest effort on defense research, and a moderate effort on miniaturization, I can field a single frigate (my terminology) based on a small hull up against an opponent fleet with three "heavy fighters" (again, small hull) and destroy them all, every time, with no damage in the majority of the encounters. My ship is 0/0/4 - 10/18/0; the opponents are usually 0/3/0 - 0/0/0. A mor
