In my bespoke setting most ships are spherical because it saves on construction cost and structural integrity. The smallest is about 20 m in diameter. Under this size they cannot have a jump field, again in my setting. That’s about 300 tons in Traveller.
In that same setting, most ships are at least 50 m in diameter. Which is close to 5,000 tons. The largest craft are about 300 m in diameter, which is approximately 1,000,000 tons. Space stations can be 10 times the size but the jump field becomes unstable over 400 m in diameter.