GM actually took pity on us and provided balanced fleet composition before, even if no-one apparently paid attention.
So, 30-ship fleet is something like:
x4 Leos
x8 Libra
x6 Scorpio
x8 Crux
x4 Aries
Extra 10 in 40-ship fleet probably can lean toward specialists designs such as Sagittarius or Lupus, but our current fleets are actually short on their primary striking power.
An ideal fleet (in a 20 Ships Task Force), from my POV for you, would be 4 Carriers, 3~4 Heavy Cruiser Brawlers, 4~6 Light Cruiser Lineholders, 4~6 Destroyer/Frigate Skirmishers, and 2~4 Destroyer/Frigate Scouts. If you are operating with a 30 Ship Task Force, add 4 more Carriers and up the Skirmishers and Scouts.
So, 30-ship fleet is something like:
x4 Leos
x8 Libra
x6 Scorpio
x8 Crux
x4 Aries
Extra 10 in 40-ship fleet probably can lean toward specialists designs such as Sagittarius or Lupus, but our current fleets are actually short on their primary striking power.