I just faced the Locust Fleetword with 22 cruisers (me human).
I had several Disruptor/PD/Fusion cruisers and several Disruptor/Armor/Fusion ones + a disruptor CNC. LAser PD in all small mounts and phasers in mediums.
Lost the planet, but the battle ended with me still having several cruisers on my reserves list!

Wasn't able to bring it down since I lost my only CNC half way trough the battle, and once all of his drones were dead I couldn't cycle my flyswatters (PD) with maulers (armor), so I didn't do enough damage.
Still, now I know how to bring the sucker down cheaply. Shame I can't save the friggin planet.