A frequently repeated leitmotif in the Foundation stories is that Empire's stuff is colossal: a colossal expanse, colossal urbanized planets, colossal nuclear generators, colossal war fleets composed of colossal spaceships. Instead, it is often implied that the Foundation's technology is miniaturized, like its power units and force fields.
Is also implied that Foundation's spacecraft are relatively small. Not only because of the miniaturization but because during the collapse of the Empire in the peripheral areas the scattered successor political units of the Empire, e.g. Terminus, the Four Kingdoms or Askone, had to improvise with small ships for civilian use.
But I don't recall at any point a clear figure expressing the size of a spaceship, of any of the types that appear in the story.
In many passages of Foundation very small ships appear, equivalent to a pleasure yacht, for the use of at most four or five people, such as those used by Bayta Darell in the story of the Mule or the one used by Arkady Darell to escape from Terminus at the beginning of her involvement with the Second Foundation.
In other passages it is implied that there are larger spaceships, with crews of dozens of people, like that trader ship in which Hober Mallow arrives on Korell in which he has to communicate with parts of his crew remotely. But in that same story a few pages later a hostile encounter between a similar Foundation ship and an Empire warship is described and the massive size difference is abundantly clear.
One gets the impression that it is a difference comparable to the famous opening scene of Star Wars Episode IV where Princess Leia's ship is intercepted by a star destroyer.
But, impressions aside, what is the typical size of a Foundation pleasure ship, a Foundation commercial ship, and an Imperial warship, expressed in meters or metric tons?
Is there any clear figure in the materials written by Isaac Asimov or in any source that can be considered canon?