Chern, I got to the 80 million ton figure by starting with the length of the thing, 1700m, and fudging backwards with the old Traveller design system; they started with volume and worked length from there, I did it the other way. Basically, the volume of a ship is equal to the volume of a sphere whose radius is the length of the ship divided by a factor for configuration- 1.75 for slab, 2.5 for wedge, etc.

I called the Omega a needle configuration- odd with the rotating bit, I know- factor 3.5, which brought it out at around fifty- seven million cubic metres. That much is calculation. The I simply guessed at the density of the ship, picking a figure of 1.4 tons/m3- enough heavy machinery, hardened hull, etc, to make the ship 1.4 times as dense as water (I don't think I actually need to explain this bit to you, Chern, this is just showing my working)- which made the eighty million figure for the actual mass.

That is big, but EA ships do look like fairly hefty pieces of kit. I don't think I'd peg anyone else's ships that high, maybe Minbari at 0.8 or even 0.7, Centauri around .8 or .85, Narn maybe 1.2 or 1.3. This is just a fudge, estimating overall roughness of construction, and may be wildly out, but it seemed a reasonable estimate at the time.