I just had a game vs AI I turtled in for all 16 caps. I farmed XP until everything was level 6 or higher, I went out with 2 marzas, 9 Kols and 5 Dunovs. Then I took them out to look for a good fight. I found a nice fully upgraded advent starbase. I attacked and found out you can destroy those really fast with the machine gun guass cannons from 9 Kols at once.
Fully teched out, you can park them all under a starbase with docking booms + finest hour, you will have a +9.5 antimatter per second. Add with culture bonus and naturally higher antimatter restore rate of high level ships with upgrades. Then you end up with never running out of antimatter. The only limiting factor is the cooldown times.