There's one dirty trick you can use against the AI.  Split your fleet into two groups, and then scout out his empire to see where he's positioned his main force.  Attack the opposite side of his empire.  He will immediately head there to protect it (you may want to equip some bombers to quickly destroy any phase stabilizer).  As soon as he's a few jumps away, launch your second fleet to attack the newly defenseless front.  As soon as he shows up to defend either location, run away.  As soon as he leaves to defend the other location, come back to start fighting.  It's actually possible to destroy an AI's entire empire without ever confronting its fleet.  The AI doesn't know how to split its forces up into multiple groups, and just runs around in circles all day while you slowly gain territory.

Missile barrage is a great way to clear a huge fleet value of enemy troops, but there are some other abilities you should use.  Flak barrage from the Kol battleship is your best method to control enemy strike craft.  You do need to time it right to maximize the number of targets, so auto-cast must be turned off.  Dunov with shield restore is also great, but don't under-estimate EMP or magnetize.  Culture cannot be under-estimated.  If you have cultural supremacy where the battle takes place, you gain greatly increased anti-matter regeneration, which is critical for your Hoshikos.  Combined with a Kol suppressing strike craft, Hoshikos can keep cruisers and frigates from dealing too much damage while repairing what damage gets done.

Assuming this is not Entrenchment first of all. Second, spamming Novaliths would cost order of magnetutde more than couple cap ships.

yeah but he said he controls like 65% of the galaxy. presumably money is no object and he can easily build like 10 Novaliths if he wanted to. seems obvious what to do. 

yeah, you've got a good point. but its the AI so i'm just gonna assume novaliths work fine. AI never uses the interesting stuff. AI won't even build self-destruct with the Argonev. they generally don't know how to use SB's at all. 

if you don't have entrenchment then just nova the living $hit out of the AI. time will be on your side (quoted from the great Cykur), especially since your TEConomy should be going strong at this point. The AI won't build kosturas so stack the border worlds with defenses. culture will also take away his damage bonus. looking at your fleet composition, i noticed there weren't any carriers. you'll need carriers for this! also, did you have the chance to take him out? this doesn't always apply in online, but i think late-game vasari AI is deadliest AI, especially when generally uncontested early-mid game. play to TEC's strengths and you should be able to pull through.

Subverters in large numbers are insanely effective in large numbers.  I recently played against 6 unfair AIs on the map Maelstrom, which is currently my favorite map to play.  Vasari have a hard time dealing with kodiaks and hoshikos because the kodiaks can get right in your fleets face and blast away.  Then the hoshiskos repair everything and everything just goes to hell.  I finally built some subverters and my war with that TEC turned around completely. 

You should check out the gravity well where the fleet is stationed and make sure to locate and destroy and phase jump inhibitors.  I don't think using the scouts time bomb will be particularly effective due to the phasic shielding that vasar structures get, so you'll have to do it the messy way with a fleet.  Also I hope you're using the most up to date version of SOASE.  Older versions (pre 1.05 I believe) allowed subverters to lock down even cap ships and that is very difficult to fight against when dealing with subverters in large numbers.  After that the best approach is get a bunch of marzas leveled up through attrition. 

I'm assuming that you want to take this fleet head-on in a grand epic style space battle and not just win the map. If you wanted to just win, novalith cannons would be the best as has been previously suggested.

I've actually tried the arcova strategy before to try raiding against vasari AI.  You really need ALOT of them.  That phasic barrier thing really makes them alot less effective.  If you wanted to blow up one or two key buildings it might work, but blowing up buildings through out multiple planets definitely didn't work out for me.  Waiting for the barrier to wear off also isn't really an option if you want to get out of there before a fleet arrives.