I do tend to use some navy conventions..... but use a combined terminology remeniscient of the age of sail, as well as WW1 and WW2.
The specific terms also vary depending on the race, or faction, that I am running. One of my human factions fields "frigates" that are about Hull 4, while another human faction has them listed at about hull 7 - 8...
The largets ship I routinely field is a 10 - 12... and rarely have more than one or two of those on the board... I tend to favor hull ranges 4 - 10 as my primary combatant ships.. with the 1 - 3 ranges as support, or specialized.. and anything 11 and over fairly mission specific (carriers, or specific heavy combat designs). The largest ships I field are approximately Hull 14....and those are extremely rare.....
I have gone larger for specific scenario games, but I prefer the smaller sizes for general pick up games, or when I run some of my own factions.
In my opinion... the larger ships are expensive enough that I expect them to be very rare... if fielded at all... just due to cost and manufacturing times. Being that I used to work for Northrupp Grummen Newport News, and have actually worked in shipbuilding.... I've seen exactly what goes into the construction of a single ship.
For that matter, our modern Nimitz class carrier is constructed of 90,000 tons of steel. This does not include insulation, wiring, furniture, or anything else... just the steel used to build the actual ship. It takes an average of 1500 to 2500 workers per shift, 3 shifts per day (24 hour construction), spread out over a period of just more than 5 years to assemble one.... and that's with modern construction techniques, and having most of the parts and assemblies pre-fabricated. Also, once the ship is built, it goes through trials, and then comes back to the shipyard for another 6 months of final fitting based on the sea trials. The total time, to include part fabrication, and assembly is approximately 8 and a half to nine years.
I figure most star ships would be constructed in orbit, so you have to consider getting the materials and manpower to the shipyard. Even if you can do everything is space... there is a lot of logistics involved....and a high cost. And the larger the ship, the more time, money and manpower involved.....
I see a lot of small to medium ships... the large hulls would just be too expensive to risk in combat... or for normal operations.
John