The purpose of this post is to test the efficiency of various ship types against the largest combatants in the game, those of Battleship size and greater. Basically, I took equal credits worth of some of the best ship types and placed them against each supership. Obviously, you would want a balanced fleet with lots of meat when actually taking on these ships, and the purpose of this test is more to calculate who is the most efficient killer of these large ships rather than determining the exact composition of the fleet needed to take down, say, a deathstar.

I used the following tech in the battle calculator:

Armor = 26
Laser = 24
Plasma = 20
Shielding = 18
Ion = 14
Photon = 12
Disruptor = 10

The results for each ship is as follows. Those results with a (*) required multiple rounds of combat to determine a victor.

Battleship v.
50 Destroyers = failed to destroy
10 Cruisers = 4.4 remaining (1000 CR losses)*
4 Heavy Cruisers = 1.5 remaining (1000 CR losses)

In this case, both Cruisers and Heavy Cruisers are about equally efficient. You will have a higher repair bill with the Heavy Cruisers, but will not require multiple combat rounds to destroy the target.

Dreadnought v.
50 Cruisers = 23 remaining (5400 CR losses)*
20 Heavy Cruisers = 9.1 remaining (5000 CR losses)
5 Battleships = .96 remaining (8000 CR losses)

The Heavy Cruiser is the most efficient killer of Dreadnoughts.

Titan v.
250 Cruisers = failed to destroy
100 Heavy Cruisers = 53.8 remaining (23,000 CR losses)
25 Battleships = 7.73 remaining (34,000 CR losses)
5 Dreadnoughts = .69 remaining (40,000 CR losses)

The Heavy Cruiser is the most efficient killer of Titans.

Leviathan v.
400 Heavy Cruisers = 232.7 remaining (83,500 CR losses)*
100 Battleships = 43 remaining (114,000 CR losses)
20 Dreadnoughts = 5.76 remaining (140,000 CR losses)
4 Titans = .44 remaining (150,000 CR losses)

The Heavy Cruiser is the most efficient killer of Leviathans, but it takes more than one combat round to do so.

Death Star v.
1000 Heavy Cruisers = failed to destroy
250 Battleships = 107.15 remaining (284,000 CR losses)
50 Dreadnoughts = 14.3 remaining (350,000 CR losses)
10 Titans = 1.08 remaining (400,000 CR losses)

The Battleship is the most efficient killer of Death Stars

Lessons:

(1) The Heavy Cruiser is a workhorse, devistating against anything up to and including a Leviathan. A fleet with enough Heavy Cruisers doesn't really need anything more powerful unless it is taking on a Death Star.

(2) While Cruisers are very good ships, Heavy Cruisers at least are needed in order to take down the larger combatants.

(3) Dreadnoughts and Titans appear to have limited value. Not very efficient against other ships types, and usually too small to be used to take bases without losses (like Levis and DS can).

(4) Super ships such as Death Stars are very vulnerable. 500,000 credits worth of battleships can kill them and still have 216,000 worth of ships remaining. That's almost a 2-1 casualty ratio against the most feared ship in the game. If you have them, make sure to keep them behind a powerful screen of Heavy Cruisers and lower