My size chart for my finished ships. I have the smaller ships, but they would be too small to show.
From top to bottem: (Prometheus, Daedalus, Nemesis, Hyperion)
Prometheus - Light Cruiser
Daedalus - Battle Cruiser
Nemesis - Battle Carrier
Hyperion - Destroyer
First came the light cruiser. I loved this ship, so In my little stories, her class was not discontinued and they used them in squads of 5 with 2 Daedalus class ships. The Light cruiser can hold a maximum of 8 fighters, and have half the railguns of its successor. It was fitted with two beam canons in later years.
Daedalus class ships were made in a variety of rolls, being carriers to transport goods to outposts (Atlantis) and cruisers that fight in battle and weapons platforms.
Battle Carriers were meant to accompany Battle Cruisers into battle. Holding more fighters and a greater amount of rail-guns/pulse canons, the Battle Carrier can handle herself in any fight.
Destroyers are meant to be powerful ships. They can take out a whole fleet of battle cruisers and not get a scratch. They have ion beam canons, pulse plasma canons and advanced rail-guns mounted all over the ship. They even used the extra room to have the nose a hanger bay to hold any sort of bombers and fighters.