I'm a beginner in GC2, having bought the entire package only a few weeks ago.
But have you tried stacking military starbases?
In combination with tiny/smull hulls, and if it's TA some HP modules on them to maximize firstly firepower and secondly survival rate, that's actually a very good suggestion.
You might also consider (in TA only) using an Atlas module and either one or zero weapons on a huge hull, filling up the rest with defenses, and fleeting it up with enough tiny or smalls (full of weapons but an hp mod or two couldn't hurt) to hit your logistics cap. The Atlas module makes the huge hulled ship the primary target, so you don't lose any tinies, and with maxed out defense, it should take a while to die to even 25 fleeted pirate ships.
Your other option would be suicide dreadnaughts, all attack/no defense in fleets of one. Due to how combat works in DA and to a lesser extent TA, in a large number of instances fleets don't actually help you, and I'm fairly positive this is one of those situations.
Quite some time ago I had a Peacekeeper event where they were roaming the galaxy in fleets of 15-20 ships, with each ship at 400 beam attack/1400 beam defense, but I eventually managed to defeat all of them, simply because they don't get reinforcements.