made just 2 new tests and it doesn't look good for the adjudicators.
all ships had weapons tech up to tier 5, starbase had full tech, 2 weapons, 2 hull, 2 fighter and 2 random other upgrades i didn't see.
1st fleet consisting of 3x capitals lvl 10, 30x illuminators, 10x guardians and 10x subjugators
fleet won with not even a scratch on it 
2nd fleet consisting of 1 lvl 10 progenitor, 40 illuminators and 10 guardians
fleet won with just 4 illuminators lost
3nd fleet consisting of 20x adjudicators
fleet won but lost 10 of them due to the fighters.
the starbase was on a naked uninhabited planet with no other defenses left whatsoever.
now i'm really convinced that adjudicators are in fact not starbase killers but a very weak structure killer which needs desperate support from fighters and healing-ships.
hitting 5 targets at once can really clear any planet defense pretty quick if you keep them safe, but for the starbase they just need too much time.