Chasing Shadows: How to break Kristan Parthus's armor tank?

I cannot figure out how to break Kristan Parthus's armor tank. My own health is not an issue, I am orbiting at 500m and he can't hit me. I am using:

Rifter

3x 200mm Autocannon I, Fusion

1x Rocket Launcher I, Fusion

2x Gyrostabilizer I

Is there anything I can do to do enough damage to kill him alone? I have gotten him as low as ~33% armor, though I am not sure how this happens, since he is able to heal back to full after.

EDIT AS I WAS TYPING THIS: Got him down to 23% structure (though he is back to 75% armor now), guess I'll just sit on him until he dies or I run out of ammo and pray for luck? Surely there has to be a better way?

EDIT EDIT: spent a bunch of money on 3x 200mm Light Gallium Machine Gun I, went back, he died almost like he didn't regen his armor at all. 5 DPS makes that much difference, I suppose.