There used to be an awesome diagram that depicted what beats what that would help you out in deciding I think, but it's from entrenchment and doesn't include a few ships...mayhap I'll get bored this week and make an updated one...

  As for fleets, I can't really give a good answer, but you should definitely have a lot of LRF(Long Range Frigates) as they are weak to fighters, rather than the bomber-swarms that late games usually have.  Also, they deal a good amount of damage for little Supply and cost.  Paired up with Flak and Light Frigates, you should be able to build a pretty good fleet around that.  (Go easy on Flak though.  They'll attack bombers and are good against fighters, but if there are no strikecraft or (Possibly corvettes?  Don't know if they are strong vs these) they are wasting space.  In Single Player, make sure you have a few scouts in case the AI decides to drop mines.  I'm not sure if Multi-Player people use mines online or not since I just do SP.

  As far as making your fleet difficult to counter, you did an okay job there.  Although 5 of any ship won't last long, depending on what the AI flags as priority targets, or whether a human player sees them as a threat.  I usually don't do less than 12-20 if I bother building a type of ship, except Envoys of course.  I would probably say 10% fewer Enforcers and Sentinels, and 20% more LRF(Or 10% more LRF/10% LF), and use the 10% you have for subverters in a 2 subverter/1 overseer ratio.

  However, there have been 2 patches since I played last, and I rarely do vasari, so don't take me too seriously.  Just my advise on what I usually do.

-Twi

Indeed.

Fighters are doing poorly against bombers even in even numbers... with lower numbers of fighters than the enemy has bombers, you are better off having bombers, too.

It's not that they're doing a poor job, it's that their hp is spread out over hundreds or thousands of individuals, not one giant ship.  This makes it harder to insta-pop a fleet of fighters, while bombers can all gang up on one big expensive target.  Fighters are fine the way they are.  Personally, I'd like to see a minor debuff to the bomber's damage multiplier towards heavy armor.  Nothing huge, but people are taking massive advantage of the current way things are.  It seems like everyone thinks bombers are the be-all-end-all against the big stuff like Titans, Caps, and SB and when that happens, there is something wrong.

-Twi

That I agree with.  But that's more of a bombers are slightly too strong issue that iI've mentioned elsewhere.  (Yeah, I know I'm gonna get flak for saying it, but when EVERY SINGLE PERSON ON THE FORUMS says bombers are the best counter to caps, titans, and SB, there is a problem...

-Twi

Then you've micro'ed your ships very poorly.

If he has a fleet of 90% carriers, you might not want to jump your capital ship into the same grav well. Let flak/corvettes and light frigates (for the carriers themselves) do their work and at the most just sit your Titan on the edge of the well for xp but ready to escape if health drops too low - carriers suck at chasing anything.