Acutally, i have few of each ships more like 8 per, although

definitely Kodiaks, and Hoshikos. Sometimes LFs or LRMs (longest ranged unit), Will bring in small amounts of Cielos, they are useful, and carriers.

There is no "perfect" fleet. What your fleet should look like always depends on the enemy fleet/defenses.

LF countered by LRF

Flak countered by LF

LRF countered by Fighters

Fighters countered by Flak

Bombers countered by Fighters

Starbases countered by anti-structure ships or bombers (or a vasari SB)

Carriers countered by LF

Heavy cruisers countered by Bombers

Support cruisers countered by LF

LRF are countered by scout when the ratio is at least 1:2 (the scouts are still cheaper)

Now, from that list LFs seem to be a good choice, but the degree of the counters varies. While LFs deal respectable damage against the abovementioned ships the counter, they get devastaded by LRF. And by devastated I mean...annihilated. The same goes for fighters when they face flak. You need to experiment a bit on what's the best balance against certain fleet compositions. E.g. illums+flak are pretty hard to counter, because you won't get rid of the flak and the flak protect the illums from fighters. Best choice would be HCs (which "counter" pretty much every ship, i.e. deal good damage against it) but they get rendered useless by repulse.

Anyway, try&error and browsing through the stickies will help!

Per fleet or total?

I generally have one main heavy hitting battle fleet, comprised of 2-3 Kol battleships, 1-2 Dunov battlecruisers, a Sova carrier, an Akkan and a dreadnought, escorted by between 15-20 Kodiaks, a handful of carriers, 4-6 Cielos, a couple flak frigates, and lots and lots of LRM frigates, Around 20 at least. My other fleets are jsut a mishmash of starships that does come kind of close to respecting that ratio, but I do like to have a small force comprising a dreadnought, some carriers, a bunch of LRM frigates and a big pile of siege frigates as a dedicated planet-killing force. If I remember, and have the pop cap, I'll either throw in an Akkan (for colonizing) or keep a colony frigate within a jump or two from the front, but out of harm's way.